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T4XB Low Output

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  • Tom
    Hi all...I have a T4XB that was completely gone over by well known expert Jeff Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It
    Message 1 of 25 , Aug 1, 2012
      Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had at least 110-120 output. Now all of a sudden I can only tune it to a max of 55 watts. This is across all bands into Cantenna dummy load (and on air). I am not an expert by any means on trouble shooting Drake rigs. However I can perform most tasks with a little guideance. I would like a logical sequence to try and pinpoint the problem. Jeff did replace the finals when he worked on it. I have swapped all cables to no avail. I assume the next step would be to swap the 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from a friend. Just don't want to "hope and poke" myself into more problems. If someone can point me in a good direction, it would be greatly appreciated.....Thanks in advance.....Tom-WT8X
    • Garey Barrell
      Tom - Are both PA tubes lit ?? What is resonant plate current?? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service
      Message 2 of 25 , Aug 1, 2012
        Tom -

        Are both PA tubes 'lit'?? What is resonant plate current??

        73, Garey - K4OAH
        Glen Allen, VA

        Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
        and TR-4/C Service Supplement CDs
        <www.k4oah.com>

        Tom wrote:
        > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had at least 110-120 output. Now all of a sudden I can only tune it to a max of 55 watts. This is across all bands into Cantenna dummy load (and on air). I am not an expert by any means on trouble shooting Drake rigs. However I can perform most tasks with a little guideance. I would like a logical sequence to try and pinpoint the problem. Jeff did replace the finals when he worked on it. I have swapped all cables to no avail. I assume the next step would be to swap the 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from a friend. Just don't want to "hope and poke" myself into more problems. If someone can point me in a good direction, it would be greatly appreciated.....Thanks in advance.....Tom-WT8X
        >
      • Tom
        Thanks for the reply. Both PA tubes are lit. Plate current was only 120 ma. I found that as I changed the function switch from SSB to TUNE and back, the watt
        Message 3 of 25 , Aug 1, 2012
          Thanks for the reply. Both PA tubes are lit. Plate current was only 120 ma. I found that as I changed the function switch from SSB to TUNE and back, the watt meter showed a deflection. Holding the switch halfway between caused an increase in power to about 90 watts. Still low but headed in the right direction. Rocking the switch back and forth caused the reading to stay higher in TUNE position. Also plate current reading increased to 220 ma. I guess this indicates a problem in the switch contacts, which surprises me since I know Jeff cleans these thoroughly. I guess my next step is to remove the bottom cover and try to clean the contacts. Will report results later on. Let me know if this could indicate any other condition.

          --- In DrakeRadio@yahoogroups.com, Garey Barrell <k4oah@...> wrote:
          >
          > Tom -
          >
          > Are both PA tubes 'lit'?? What is resonant plate current??
          >
          > 73, Garey - K4OAH
          > Glen Allen, VA
          >
          > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
          > and TR-4/C Service Supplement CDs
          > <www.k4oah.com>
          >
          > Tom wrote:
          > > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had at least 110-120 output. Now all of a sudden I can only tune it to a max of 55 watts. This is across all bands into Cantenna dummy load (and on air). I am not an expert by any means on trouble shooting Drake rigs. However I can perform most tasks with a little guideance. I would like a logical sequence to try and pinpoint the problem. Jeff did replace the finals when he worked on it. I have swapped all cables to no avail. I assume the next step would be to swap the 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from a friend. Just don't want to "hope and poke" myself into more problems. If someone can point me in a good direction, it would be greatly appreciated.....Thanks in advance.....Tom-WT8X
          > >
          >
        • David Winfree
          Is the PA bias (no drive) still at 70mA, as read by the panel meter? ________________________________ From: Tom To:
          Message 4 of 25 , Aug 1, 2012
            Is the PA bias (no drive) still at 70mA, as read by the panel meter?



            ________________________________
            From: Tom <tcgreiner2@...>
            To: DrakeRadio@yahoogroups.com
            Sent: Wed, August 1, 2012 10:40:54 AM
            Subject: [DrakeRadio] T4XB Low Output


            Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
            Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
            at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
            watts. This is across all bands into Cantenna dummy load (and on air). I am not
            an expert by any means on trouble shooting Drake rigs. However I can perform
            most tasks with a little guideance. I would like a logical sequence to try and
            pinpoint the problem. Jeff did replace the finals when he worked on it. I have
            swapped all cables to no avail. I assume the next step would be to swap the
            12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
            a friend. Just don't want to "hope and poke" myself into more problems. If
            someone can point me in a good direction, it would be greatly
            appreciated.....Thanks in advance.....Tom-WT8X




            [Non-text portions of this message have been removed]
          • Tom
            Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune,
            Message 5 of 25 , Aug 1, 2012
              Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune, the output was low again. Rock the switch and it comes back. Either I have to clean it better or the contacts are shot. I think I can probably work it out with a couple more cleanings. I'm using regular contact cleaner. I should get some DeOxit. I have never used it but seems to be the experts choice. Thanks again...Tom

              --- In DrakeRadio@yahoogroups.com, David Winfree <davidwinfree@...> wrote:
              >
              > Is the PA bias (no drive) still at 70mA, as read by the panel meter?
              >
              >
              >
              > ________________________________
              > From: Tom <tcgreiner2@...>
              > To: DrakeRadio@yahoogroups.com
              > Sent: Wed, August 1, 2012 10:40:54 AM
              > Subject: [DrakeRadio] T4XB Low Output
              >
              >
              > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
              > Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
              > at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
              > watts. This is across all bands into Cantenna dummy load (and on air). I am not
              > an expert by any means on trouble shooting Drake rigs. However I can perform
              > most tasks with a little guideance. I would like a logical sequence to try and
              > pinpoint the problem. Jeff did replace the finals when he worked on it. I have
              > swapped all cables to no avail. I assume the next step would be to swap the
              > 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
              > a friend. Just don't want to "hope and poke" myself into more problems. If
              > someone can point me in a good direction, it would be greatly
              > appreciated.....Thanks in advance.....Tom-WT8X
              >
              >
              >
              >
              > [Non-text portions of this message have been removed]
              >
            • Garey Barrell
              Tom - Sounds like a dirty switch(s). Where is the GAIN control set in TUNE position?? The ALC should flatten out the power at about 11-12 o clock in TUNE.
              Message 6 of 25 , Aug 1, 2012
                Tom -

                Sounds like a dirty switch(s).

                Where is the GAIN control set in TUNE position?? The ALC should flatten out the power at about
                11-12 o'clock in TUNE.

                Sitting for long periods of time can cause switches to grow new sulfides which take a few switch
                operations to remove. With power OFF, exercise all the rotary switches 15-20 times end to end.
                Avoid sprays and unknown 'cleaners'. I prefer DeoxIT D100L liquid in the squeeze bottle with
                hypodermic tip. If all you can find is spray, spray a little into the cap and use a toothpick or
                tweezers to apply directly to the fixed contacts. Same treatment for tube pins won't hurt either.
                I doubt if the problem is a tube, as they typically don't just suddenly lose gain.

                As Jeff has just gone through it, I suspect the above will take care of things. Someone else asked
                about idle current, is it still 70 mA?

                73, Garey - K4OAH
                Glen Allen, VA

                Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                and TR-4/C Service Supplement CDs
                <www.k4oah.com>

                Tom wrote:
                > Thanks for the reply. Both PA tubes are lit. Plate current was only 120 ma. I found that as I changed the function switch from SSB to TUNE and back, the watt meter showed a deflection. Holding the switch halfway between caused an increase in power to about 90 watts. Still low but headed in the right direction. Rocking the switch back and forth caused the reading to stay higher in TUNE position. Also plate current reading increased to 220 ma. I guess this indicates a problem in the switch contacts, which surprises me since I know Jeff cleans these thoroughly. I guess my next step is to remove the bottom cover and try to clean the contacts. Will report results later on. Let me know if this could indicate any other condition.
                >
                > --- In DrakeRadio@yahoogroups.com, Garey Barrell <k4oah@...> wrote:
                >> Tom -
                >>
                >> Are both PA tubes 'lit'?? What is resonant plate current??
                >>
                >> 73, Garey - K4OAH
                >> Glen Allen, VA
                >>
                >> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                >> and TR-4/C Service Supplement CDs
                >> <www.k4oah.com>
                >>
                >> Tom wrote:
                >>> Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had at least 110-120 output. Now all of a sudden I can only tune it to a max of 55 watts. This is across all bands into Cantenna dummy load (and on air). I am not an expert by any means on trouble shooting Drake rigs. However I can perform most tasks with a little guideance. I would like a logical sequence to try and pinpoint the problem. Jeff did replace the finals when he worked on it. I have swapped all cables to no avail. I assume the next step would be to swap the 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from a friend. Just don't want to "hope and poke" myself into more problems. If someone can point me in a good direction, it would be greatly appreciated.....Thanks in advance.....Tom-WT8X
                >>>
              • Garey Barrell
                Tom - Possibly. You may have a cracked solder joint associated with the switches movement. If it stays flaky, use a plastic or wooden stick to apply pressure
                Message 7 of 25 , Aug 1, 2012
                  Tom -

                  Possibly. You may have a cracked solder joint associated with the switches movement. If it stays
                  flaky, use a plastic or wooden stick to apply pressure to various leads to see if you can replicate
                  it. Don't press on the wafers themselves, but on wires that are attached to them and just wiggle
                  them a little.

                  You don't mention the band you are on, but 120W is about right for 20M in TUNE, perhaps 10W low on
                  the lower bands. Brand and condition of PA tubes will also affect those numbers.

                  73, Garey - K4OAH
                  Glen Allen, VA

                  Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                  and TR-4/C Service Supplement CDs
                  <www.k4oah.com>

                  Tom wrote:
                  > Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune, the output was low again. Rock the switch and it comes back. Either I have to clean it better or the contacts are shot. I think I can probably work it out with a couple more cleanings. I'm using regular contact cleaner. I should get some DeOxit. I have never used it but seems to be the experts choice. Thanks again...Tom
                  >
                  > --- In DrakeRadio@yahoogroups.com, David Winfree <davidwinfree@...> wrote:
                  >> Is the PA bias (no drive) still at 70mA, as read by the panel meter?
                  >>
                  >>
                  >>
                  >> ________________________________
                  >> From: Tom <tcgreiner2@...>
                  >> To: DrakeRadio@yahoogroups.com
                  >> Sent: Wed, August 1, 2012 10:40:54 AM
                  >> Subject: [DrakeRadio] T4XB Low Output
                  >>
                  >>
                  >> Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
                  >> Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
                  >> at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
                  >> watts. This is across all bands into Cantenna dummy load (and on air). I am not
                  >> an expert by any means on trouble shooting Drake rigs. However I can perform
                  >> most tasks with a little guideance. I would like a logical sequence to try and
                  >> pinpoint the problem. Jeff did replace the finals when he worked on it. I have
                  >> swapped all cables to no avail. I assume the next step would be to swap the
                  >> 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
                  >> a friend. Just don't want to "hope and poke" myself into more problems. If
                  >> someone can point me in a good direction, it would be greatly
                  >> appreciated.....Thanks in advance.....Tom-WT8X
                  >>
                  >>
                • Richard Knoppow
                  ... From: Tom To: Sent: Wednesday, August 01, 2012 11:52 AM Subject: [DrakeRadio] Re: T4XB Low Output ...
                  Message 8 of 25 , Aug 1, 2012
                    ----- Original Message -----
                    From: "Tom" <tcgreiner2@...>
                    To: <DrakeRadio@yahoogroups.com>
                    Sent: Wednesday, August 01, 2012 11:52 AM
                    Subject: [DrakeRadio] Re: T4XB Low Output


                    > Thanks very much for the replies. I cleaned the function
                    > switch contacts the best I could and got the output up to
                    > 120 watts. The next time I put it in tune, the output was
                    > low again. Rock the switch and it comes back. Either I
                    > have to clean it better or the contacts are shot. I think
                    > I can probably work it out with a couple more cleanings.
                    > I'm using regular contact cleaner. I should get some
                    > DeOxit. I have never used it but seems to be the experts
                    > choice. Thanks again...Tom
                    >

                    Don't trust the switch contacts to stay clean. Deoxit
                    can work for a time but the pollutants in the air that
                    corrode switch contacts is always there especially in
                    cities. Caig Labs says that treating contacts with Deoxit
                    Gold after cleaning with regular Deoxit will protect them.
                    I have not tried this yet. However, I've had good success
                    with Tuner-Lub, a light grease meant originally for TV
                    tuners. I clean with Deoxit and when its evaporated put a
                    little Tuner-Lub on with a toothpick or similar tool. I've
                    treated switches that got flaky in a few days after cleaning
                    with this stuff and it seems to prevent oxidation for months
                    at least. I suspect that even Vaseline will work. Vaseline
                    used to be the standard for treating contacts on bridges and
                    resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                    non-conducting and are easily cleaned off with naphtha.
                    FWIW, the band switch in my TR-4 was persistently
                    intermittent, not working at all on some bands until I
                    cleaned the decks with Deoxit but would become intermittent
                    again after a couple of days. Tuner-Lub after cleaning
                    fixed this.
                    I think this also has to do with the amount of pressure
                    the spring contacts put on the wiper. I suspect its too low
                    for the wiping action to be consistent in some switches. I
                    don't have a fix for this other than perhaps replacing the
                    switches but the above method seems to work at least for a
                    reasonable time.


                    --
                    Richard Knoppow
                    Los Angeles
                    WB6KBL
                    dickburk@...
                  • Tom
                    Thanks Richard...We used to use a compound on high voltage connections that I think was call No Al-Ox or something similar to that. Mostly where aluminum
                    Message 9 of 25 , Aug 1, 2012
                      Thanks Richard...We used to use a compound on high voltage connections that I think was call "No Al-Ox" or something similar to that. Mostly where aluminum wire was connected to any sort of copper. Sounds very much like what you bare referring to. Again..thanks to all. I at least now know where to go if and when the problem crops up.

                      --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@...> wrote:
                      >
                      >
                      > ----- Original Message -----
                      > From: "Tom" <tcgreiner2@...>
                      > To: <DrakeRadio@yahoogroups.com>
                      > Sent: Wednesday, August 01, 2012 11:52 AM
                      > Subject: [DrakeRadio] Re: T4XB Low Output
                      >
                      >
                      > > Thanks very much for the replies. I cleaned the function
                      > > switch contacts the best I could and got the output up to
                      > > 120 watts. The next time I put it in tune, the output was
                      > > low again. Rock the switch and it comes back. Either I
                      > > have to clean it better or the contacts are shot. I think
                      > > I can probably work it out with a couple more cleanings.
                      > > I'm using regular contact cleaner. I should get some
                      > > DeOxit. I have never used it but seems to be the experts
                      > > choice. Thanks again...Tom
                      > >
                      >
                      > Don't trust the switch contacts to stay clean. Deoxit
                      > can work for a time but the pollutants in the air that
                      > corrode switch contacts is always there especially in
                      > cities. Caig Labs says that treating contacts with Deoxit
                      > Gold after cleaning with regular Deoxit will protect them.
                      > I have not tried this yet. However, I've had good success
                      > with Tuner-Lub, a light grease meant originally for TV
                      > tuners. I clean with Deoxit and when its evaporated put a
                      > little Tuner-Lub on with a toothpick or similar tool. I've
                      > treated switches that got flaky in a few days after cleaning
                      > with this stuff and it seems to prevent oxidation for months
                      > at least. I suspect that even Vaseline will work. Vaseline
                      > used to be the standard for treating contacts on bridges and
                      > resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                      > non-conducting and are easily cleaned off with naphtha.
                      > FWIW, the band switch in my TR-4 was persistently
                      > intermittent, not working at all on some bands until I
                      > cleaned the decks with Deoxit but would become intermittent
                      > again after a couple of days. Tuner-Lub after cleaning
                      > fixed this.
                      > I think this also has to do with the amount of pressure
                      > the spring contacts put on the wiper. I suspect its too low
                      > for the wiping action to be consistent in some switches. I
                      > don't have a fix for this other than perhaps replacing the
                      > switches but the above method seems to work at least for a
                      > reasonable time.
                      >
                      >
                      > --
                      > Richard Knoppow
                      > Los Angeles
                      > WB6KBL
                      > dickburk@...
                      >
                    • William Houghton
                      Richard, et all, Is Tuner-Lub the product name ? Who is the mfgr? A couple of my Drakes that I have cleaned with DeOxit required  2 or 3 treatments over a
                      Message 10 of 25 , Aug 1, 2012
                        Richard, et all,

                        Is "Tuner-Lub" the product name ? Who is the mfgr?

                        A couple of my Drakes that I have cleaned with DeOxit required  2 or 3
                        treatments over a few weeks to get the problems solved. I used the 5% DeOxit not
                        the 100%. The Caig datasheets that I saw for the 100% said you needed to clean
                        it off after using. That wasn't required for the 5%. I have also noticed that if
                        I don't use the gear for several weeks to months, I might have to re-treat it.

                        I used No Al Ox on my tribander but I'd never use it on a wafer switch.

                         

                        ________________________________
                        From: Tom <tcgreiner2@...>
                        To: DrakeRadio@yahoogroups.com
                        Sent: Wed, August 1, 2012 1:27:12 PM
                        Subject: [DrakeRadio] Re: T4XB Low Output

                         
                        Thanks Richard...We used to use a compound on high voltage connections that I
                        think was call "No Al-Ox" or something similar to that. Mostly where aluminum
                        wire was connected to any sort of copper. Sounds very much like what you bare
                        referring to. Again..thanks to all. I at least now know where to go if and when
                        the problem crops up.

                        --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@...> wrote:
                        >
                        >
                        > ----- Original Message -----
                        > From: "Tom" <tcgreiner2@...>
                        > To: <DrakeRadio@yahoogroups.com>
                        > Sent: Wednesday, August 01, 2012 11:52 AM
                        > Subject: [DrakeRadio] Re: T4XB Low Output
                        >
                        >
                        > > Thanks very much for the replies. I cleaned the function
                        > > switch contacts the best I could and got the output up to
                        > > 120 watts. The next time I put it in tune, the output was
                        > > low again. Rock the switch and it comes back. Either I
                        > > have to clean it better or the contacts are shot. I think
                        > > I can probably work it out with a couple more cleanings.
                        > > I'm using regular contact cleaner. I should get some
                        > > DeOxit. I have never used it but seems to be the experts
                        > > choice. Thanks again...Tom
                        > >
                        >
                        > Don't trust the switch contacts to stay clean. Deoxit
                        > can work for a time but the pollutants in the air that
                        > corrode switch contacts is always there especially in
                        > cities. Caig Labs says that treating contacts with Deoxit
                        > Gold after cleaning with regular Deoxit will protect them.
                        > I have not tried this yet. However, I've had good success
                        > with Tuner-Lub, a light grease meant originally for TV
                        > tuners. I clean with Deoxit and when its evaporated put a
                        > little Tuner-Lub on with a toothpick or similar tool. I've
                        > treated switches that got flaky in a few days after cleaning
                        > with this stuff and it seems to prevent oxidation for months
                        > at least. I suspect that even Vaseline will work. Vaseline
                        > used to be the standard for treating contacts on bridges and
                        > resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                        > non-conducting and are easily cleaned off with naphtha.
                        > FWIW, the band switch in my TR-4 was persistently
                        > intermittent, not working at all on some bands until I
                        > cleaned the decks with Deoxit but would become intermittent
                        > again after a couple of days. Tuner-Lub after cleaning
                        > fixed this.
                        > I think this also has to do with the amount of pressure
                        > the spring contacts put on the wiper. I suspect its too low
                        > for the wiping action to be consistent in some switches. I
                        > don't have a fix for this other than perhaps replacing the
                        > switches but the above method seems to work at least for a
                        > reasonable time.
                        >
                        >
                        > --
                        > Richard Knoppow
                        > Los Angeles
                        > WB6KBL
                        > dickburk@...
                        >




                        [Non-text portions of this message have been removed]
                      • Steve Wedge
                        Tom, refresh my memory on which switch it is that you re rocking. TNX Steve Wedge, W1ES/4 Time flies like an arrow; fruit flies like a banana. All my computers
                        Message 11 of 25 , Aug 1, 2012
                          Tom, refresh my memory on which switch it is that you're rocking.

                          TNX

                          Steve Wedge, W1ES/4

                          Time flies like an arrow; fruit flies like a banana.


                          All my computers have my signature with various pearls of wisdom appended thereto.



                          From: Tom
                          Sent: Wednesday, August 01, 2012 2:52 PM
                          To: DrakeRadio@yahoogroups.com
                          Subject: [DrakeRadio] Re: T4XB Low Output



                          Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune, the output was low again. Rock the switch and it comes back. Either I have to clean it better or the contacts are shot. I think I can probably work it out with a couple more cleanings. I'm using regular contact cleaner. I should get some DeOxit. I have never used it but seems to be the experts choice. Thanks again...Tom

                          --- In DrakeRadio@yahoogroups.com, David Winfree <davidwinfree@...> wrote:
                          >
                          > Is the PA bias (no drive) still at 70mA, as read by the panel meter?
                          >
                          >
                          >
                          > ________________________________
                          > From: Tom <tcgreiner2@...>
                          > To: DrakeRadio@yahoogroups.com
                          > Sent: Wed, August 1, 2012 10:40:54 AM
                          > Subject: [DrakeRadio] T4XB Low Output
                          >
                          >
                          > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
                          > Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
                          > at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
                          > watts. This is across all bands into Cantenna dummy load (and on air). I am not
                          > an expert by any means on trouble shooting Drake rigs. However I can perform
                          > most tasks with a little guideance. I would like a logical sequence to try and
                          > pinpoint the problem. Jeff did replace the finals when he worked on it. I have
                          > swapped all cables to no avail. I assume the next step would be to swap the
                          > 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
                          > a friend. Just don't want to "hope and poke" myself into more problems. If
                          > someone can point me in a good direction, it would be greatly
                          > appreciated.....Thanks in advance.....Tom-WT8X
                          >
                          >
                          >
                          >
                          > [Non-text portions of this message have been removed]
                          >





                          [Non-text portions of this message have been removed]
                        • David Winfree
                          In the 60 s to 80 s , TV s used wafer switches for VHF band channel selection. I was a repairman, but when faced with a noisy tuner due to the wafers, it got
                          Message 12 of 25 , Aug 1, 2012
                            In the 60's to 80's , TV's used wafer switches for VHF band channel selection.
                            I was a repairman, but when faced with a noisy tuner due to the wafers, it got
                            sent to a tuner rebuild shop. The wafer switches were returned with a green
                            grease applied by hand to the precious metal. Nothing I tried as a spray would
                            keep the tuner fixed for more than a few months. I worked in Florida, the land
                            of 80% humidity almost year round. Tech Spray sold me a lot of "blue shower" and
                            "blue stuff" for this purpose. Worked, just not for very long. I do think a
                            protective film to reduce the Ag oxidation is key. Since those old days, DeOxit
                            has come along. So far, my drake twins have responded well to the 1/2 combo
                            treatment.

                            WB4SPT



                            ________________________________
                            From: William Houghton <rdrbill@...>
                            To: DrakeRadio@yahoogroups.com
                            Sent: Wed, August 1, 2012 4:39:40 PM
                            Subject: Re: [DrakeRadio] Re: T4XB Low Output


                            Richard, et all,

                            Is "Tuner-Lub" the product name ? Who is the mfgr?

                            A couple of my Drakes that I have cleaned with DeOxit required 2 or 3
                            treatments over a few weeks to get the problems solved. I used the 5% DeOxit not

                            the 100%. The Caig datasheets that I saw for the 100% said you needed to clean
                            it off after using. That wasn't required for the 5%. I have also noticed that if

                            I don't use the gear for several weeks to months, I might have to re-treat it.

                            I used No Al Ox on my tribander but I'd never use it on a wafer switch.



                            ________________________________
                            From: Tom <tcgreiner2@...>
                            To: DrakeRadio@yahoogroups.com
                            Sent: Wed, August 1, 2012 1:27:12 PM
                            Subject: [DrakeRadio] Re: T4XB Low Output


                            Thanks Richard...We used to use a compound on high voltage connections that I
                            think was call "No Al-Ox" or something similar to that. Mostly where aluminum
                            wire was connected to any sort of copper. Sounds very much like what you bare
                            referring to. Again..thanks to all. I at least now know where to go if and when
                            the problem crops up.

                            --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@...> wrote:
                            >
                            >
                            > ----- Original Message -----
                            > From: "Tom" <tcgreiner2@...>
                            > To: <DrakeRadio@yahoogroups.com>
                            > Sent: Wednesday, August 01, 2012 11:52 AM
                            > Subject: [DrakeRadio] Re: T4XB Low Output
                            >
                            >
                            > > Thanks very much for the replies. I cleaned the function
                            > > switch contacts the best I could and got the output up to
                            > > 120 watts. The next time I put it in tune, the output was
                            > > low again. Rock the switch and it comes back. Either I
                            > > have to clean it better or the contacts are shot. I think
                            > > I can probably work it out with a couple more cleanings.
                            > > I'm using regular contact cleaner. I should get some
                            > > DeOxit. I have never used it but seems to be the experts
                            > > choice. Thanks again...Tom
                            > >
                            >
                            > Don't trust the switch contacts to stay clean. Deoxit
                            > can work for a time but the pollutants in the air that
                            > corrode switch contacts is always there especially in
                            > cities. Caig Labs says that treating contacts with Deoxit
                            > Gold after cleaning with regular Deoxit will protect them.
                            > I have not tried this yet. However, I've had good success
                            > with Tuner-Lub, a light grease meant originally for TV
                            > tuners. I clean with Deoxit and when its evaporated put a
                            > little Tuner-Lub on with a toothpick or similar tool. I've
                            > treated switches that got flaky in a few days after cleaning
                            > with this stuff and it seems to prevent oxidation for months
                            > at least. I suspect that even Vaseline will work. Vaseline
                            > used to be the standard for treating contacts on bridges and
                            > resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                            > non-conducting and are easily cleaned off with naphtha.
                            > FWIW, the band switch in my TR-4 was persistently
                            > intermittent, not working at all on some bands until I
                            > cleaned the decks with Deoxit but would become intermittent
                            > again after a couple of days. Tuner-Lub after cleaning
                            > fixed this.
                            > I think this also has to do with the amount of pressure
                            > the spring contacts put on the wiper. I suspect its too low
                            > for the wiping action to be consistent in some switches. I
                            > don't have a fix for this other than perhaps replacing the
                            > switches but the above method seems to work at least for a
                            > reasonable time.
                            >
                            >
                            > --
                            > Richard Knoppow
                            > Los Angeles
                            > WB6KBL
                            > dickburk@...
                            >

                            [Non-text portions of this message have been removed]




                            [Non-text portions of this message have been removed]
                          • Tom
                            It s the function switch. Rocking between SSB and TUNE. I m a rocker from way back but this is different.
                            Message 13 of 25 , Aug 1, 2012
                              It's the function switch. Rocking between SSB and TUNE. I'm a rocker from way back but this is different.

                              --- In DrakeRadio@yahoogroups.com, "Steve Wedge" <w1es1982@...> wrote:
                              >
                              > Tom, refresh my memory on which switch it is that you're rocking.
                              >
                              > TNX
                              >
                              > Steve Wedge, W1ES/4
                              >
                              > Time flies like an arrow; fruit flies like a banana.
                              >
                              >
                              > All my computers have my signature with various pearls of wisdom appended thereto.
                              >
                              >
                              >
                              > From: Tom
                              > Sent: Wednesday, August 01, 2012 2:52 PM
                              > To: DrakeRadio@yahoogroups.com
                              > Subject: [DrakeRadio] Re: T4XB Low Output
                              >
                              >
                              >
                              > Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune, the output was low again. Rock the switch and it comes back. Either I have to clean it better or the contacts are shot. I think I can probably work it out with a couple more cleanings. I'm using regular contact cleaner. I should get some DeOxit. I have never used it but seems to be the experts choice. Thanks again...Tom
                              >
                              > --- In DrakeRadio@yahoogroups.com, David Winfree <davidwinfree@> wrote:
                              > >
                              > > Is the PA bias (no drive) still at 70mA, as read by the panel meter?
                              > >
                              > >
                              > >
                              > > ________________________________
                              > > From: Tom <tcgreiner2@>
                              > > To: DrakeRadio@yahoogroups.com
                              > > Sent: Wed, August 1, 2012 10:40:54 AM
                              > > Subject: [DrakeRadio] T4XB Low Output
                              > >
                              > >
                              > > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
                              > > Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
                              > > at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
                              > > watts. This is across all bands into Cantenna dummy load (and on air). I am not
                              > > an expert by any means on trouble shooting Drake rigs. However I can perform
                              > > most tasks with a little guideance. I would like a logical sequence to try and
                              > > pinpoint the problem. Jeff did replace the finals when he worked on it. I have
                              > > swapped all cables to no avail. I assume the next step would be to swap the
                              > > 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
                              > > a friend. Just don't want to "hope and poke" myself into more problems. If
                              > > someone can point me in a good direction, it would be greatly
                              > > appreciated.....Thanks in advance.....Tom-WT8X
                              > >
                              > >
                              > >
                              > >
                              > > [Non-text portions of this message have been removed]
                              > >
                              >
                              >
                              >
                              >
                              >
                              > [Non-text portions of this message have been removed]
                              >
                            • Steve Wedge
                              That s a bit curious and somehow sounds familiar. When using TUNE or CW, you get the relay to briefly click but then nothing happens. IF you ve tried
                              Message 14 of 25 , Aug 1, 2012
                                That's a bit curious and somehow sounds familiar. When using TUNE or CW, you get the relay to briefly click but then nothing happens. IF you've tried adjusting the ANTI-VOX/SIDETONE and VOX controls already, check C132. If it hasn't been changed yet, it may be open. Rocking the switch is connecting some points in the position between the detents that are probably bypassing V9A.

                                Just a hunch...

                                Steve Wedge, W1ES/4

                                Time flies like an arrow; fruit flies like a banana.


                                All my computers have my signature with various pearls of wisdom appended thereto.



                                From: Tom
                                Sent: Wednesday, August 01, 2012 8:56 PM
                                To: DrakeRadio@yahoogroups.com
                                Subject: [DrakeRadio] Re: T4XB Low Output



                                It's the function switch. Rocking between SSB and TUNE. I'm a rocker from way back but this is different.

                                --- In DrakeRadio@yahoogroups.com, "Steve Wedge" <w1es1982@...> wrote:
                                >
                                > Tom, refresh my memory on which switch it is that you're rocking.
                                >
                                > TNX
                                >
                                > Steve Wedge, W1ES/4
                                >
                                > Time flies like an arrow; fruit flies like a banana.
                                >
                                >
                                > All my computers have my signature with various pearls of wisdom appended thereto.
                                >
                                >
                                >
                                > From: Tom
                                > Sent: Wednesday, August 01, 2012 2:52 PM
                                > To: DrakeRadio@yahoogroups.com
                                > Subject: [DrakeRadio] Re: T4XB Low Output
                                >
                                >
                                >
                                > Thanks very much for the replies. I cleaned the function switch contacts the best I could and got the output up to 120 watts. The next time I put it in tune, the output was low again. Rock the switch and it comes back. Either I have to clean it better or the contacts are shot. I think I can probably work it out with a couple more cleanings. I'm using regular contact cleaner. I should get some DeOxit. I have never used it but seems to be the experts choice. Thanks again...Tom
                                >
                                > --- In DrakeRadio@yahoogroups.com, David Winfree <davidwinfree@> wrote:
                                > >
                                > > Is the PA bias (no drive) still at 70mA, as read by the panel meter?
                                > >
                                > >
                                > >
                                > > ________________________________
                                > > From: Tom <tcgreiner2@>
                                > > To: DrakeRadio@yahoogroups.com
                                > > Sent: Wed, August 1, 2012 10:40:54 AM
                                > > Subject: [DrakeRadio] T4XB Low Output
                                > >
                                > >
                                > > Hi all...I have a T4XB that was completely "gone over" by well known expert Jeff
                                > > Covelli (WA8SAJ)about a year ago. It has seen little use since that time. It had
                                > > at least 110-120 output. Now all of a sudden I can only tune it to a max of 55
                                > > watts. This is across all bands into Cantenna dummy load (and on air). I am not
                                > > an expert by any means on trouble shooting Drake rigs. However I can perform
                                > > most tasks with a little guideance. I would like a logical sequence to try and
                                > > pinpoint the problem. Jeff did replace the finals when he worked on it. I have
                                > > swapped all cables to no avail. I assume the next step would be to swap the
                                > > 12BY7A driver. I don't have access to a lot of tubes but can "borrow" a few from
                                > > a friend. Just don't want to "hope and poke" myself into more problems. If
                                > > someone can point me in a good direction, it would be greatly
                                > > appreciated.....Thanks in advance.....Tom-WT8X
                                > >
                                > >
                                > >
                                > >
                                > > [Non-text portions of this message have been removed]
                                > >
                                >
                                >
                                >
                                >
                                >
                                > [Non-text portions of this message have been removed]
                                >





                                [Non-text portions of this message have been removed]
                              • Richard Knoppow
                                ... From: William Houghton To: Sent: Wednesday, August 01, 2012 1:39 PM Subject: Re: [DrakeRadio] Re: T4XB
                                Message 15 of 25 , Aug 1, 2012
                                  ----- Original Message -----
                                  From: "William Houghton" <rdrbill@...>
                                  To: <DrakeRadio@yahoogroups.com>
                                  Sent: Wednesday, August 01, 2012 1:39 PM
                                  Subject: Re: [DrakeRadio] Re: T4XB Low Output


                                  Richard, et all,

                                  Is "Tuner-Lub" the product name ? Who is the mfgr?

                                  A couple of my Drakes that I have cleaned with DeOxit
                                  required 2 or 3
                                  treatments over a few weeks to get the problems solved. I
                                  used the 5% DeOxit not
                                  the 100%. The Caig datasheets that I saw for the 100% said
                                  you needed to clean
                                  it off after using. That wasn't required for the 5%. I have
                                  also noticed that if
                                  I don't use the gear for several weeks to months, I might
                                  have to re-treat it.

                                  I used No Al Ox on my tribander but I'd never use it on a
                                  wafer switch.

                                  Tunerlub is made by General Cement. I did a search for
                                  the MSDS, it turns out to be pure petrolatum, AKA, Vaseline
                                  with less than 20 PPM of BHT (butylated hydroxytoluene) in
                                  it. BHT us an anti-oxidant used in food packaging. Its
                                  probably there to prevent the stuff from turning brown. I
                                  think plain Vaseline would do as well.


                                  --
                                  Richard Knoppow
                                  Los Angeles
                                  WB6KBL
                                  dickburk@...
                                • w6mqi
                                  Dang I learn something everyday on Drake radio (Vaseline)I m going to have to try this on my T4XB the problem child. I seem to remember with a C-line I had
                                  Message 16 of 25 , Aug 2, 2012
                                    Dang I learn something everyday on Drake radio (Vaseline)I'm going to have to try this on my T4XB the problem child. I seem to remember with a C-line I had years ago I never had switch issues they would set idle for months without any switch contact issues at all. Now with my B-line the Deoxit is always on standby I guess once the oxidation process starts it's constant maintenance with these old boys.

                                    73,Dave



                                    --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@...> wrote:
                                    >
                                    >
                                    > ----- Original Message -----
                                    > From: "William Houghton" <rdrbill@...>
                                    > To: <DrakeRadio@yahoogroups.com>
                                    > Sent: Wednesday, August 01, 2012 1:39 PM
                                    > Subject: Re: [DrakeRadio] Re: T4XB Low Output
                                    >
                                    >
                                    > Richard, et all,
                                    >
                                    > Is "Tuner-Lub" the product name ? Who is the mfgr?
                                    >
                                    > A couple of my Drakes that I have cleaned with DeOxit
                                    > required 2 or 3
                                    > treatments over a few weeks to get the problems solved. I
                                    > used the 5% DeOxit not
                                    > the 100%. The Caig datasheets that I saw for the 100% said
                                    > you needed to clean
                                    > it off after using. That wasn't required for the 5%. I have
                                    > also noticed that if
                                    > I don't use the gear for several weeks to months, I might
                                    > have to re-treat it.
                                    >
                                    > I used No Al Ox on my tribander but I'd never use it on a
                                    > wafer switch.
                                    >
                                    > Tunerlub is made by General Cement. I did a search for
                                    > the MSDS, it turns out to be pure petrolatum, AKA, Vaseline
                                    > with less than 20 PPM of BHT (butylated hydroxytoluene) in
                                    > it. BHT us an anti-oxidant used in food packaging. Its
                                    > probably there to prevent the stuff from turning brown. I
                                    > think plain Vaseline would do as well.
                                    >
                                    >
                                    > --
                                    > Richard Knoppow
                                    > Los Angeles
                                    > WB6KBL
                                    > dickburk@...
                                    >
                                  • Garey Barrell
                                    I guess Vaseline is ok, although it sure sounds like it would be a serious dirt attractant. Also, the petroleum base is a little concerning. I ve been using
                                    Message 17 of 25 , Aug 2, 2012
                                      I guess Vaseline is ok, although it sure sounds like it would be a serious dirt attractant. Also,
                                      the petroleum base is a little concerning.

                                      I've been using D100L for 30+ years, and have yet to re-treat a switch. The primary problem with
                                      rotary switches is the formation of silver sulfide, (black stuff,) formed when the silver plating on
                                      the switch contacts comes in contact with sulfurous compounds in the atmosphere. There is 'some'
                                      sulfur in just about location, much more in some places, paper manufacturing is one major source.
                                      Silver sulfide IS soft, and IS conductive. Once formed however, it stops oxidizing and protects the
                                      remaining silver surface. 'Mechanical' silver polishes (Brasso, etc.,) work by 'sanding' off the
                                      silver oxide, necessarily taking whatever silver is contained to the trash. The nice clean surface
                                      then starts forming silver sulfide ALL over it, removing still more silver by combining to form new
                                      sulfides

                                      DeoxIT says to use D100L on switch contacts and then wipe off with Q-Tip etc. Wiping removes ALL
                                      the oxidation, similar to silver polish, although DeoxIT leaves a protectant/lubricant even when
                                      wiped off.

                                      I don't like using tools around quite delicate switch contacts such as those on the Drake wafer
                                      switches. Perhaps my shaky hands have made me even more conscious of risk, but I have seen more
                                      than a few switches with 'sprung' contacts as the result of catching on a Q-Tip or being displaced
                                      by a harder tool while 'cleaning'.

                                      My personal opinion is that DexoIT DL100 applied in drops to the contacts of small rotary switches,
                                      and then operating that switch, will result in a switch rotor with a bright silver line where the
                                      fixed contact is sliding. Another drop will then coat and lubricate that line, and the switch is
                                      good. The advantage also is that ONLY the contact area is exposed to the air, while the remainder of
                                      the rotor is still protected by the sulfide layer. Now if the rotor is _corroded_ this may not be
                                      sufficient and more rigorous cleaning might be required. Obviously dirt, sand, corrosion, etc.,
                                      must be removed first.

                                      My radios are not stored in the barn, but either in air conditioned living space or an attached
                                      _dry_ garage, and re-treating has never been required, even after storage for years.

                                      As my baby sister used to say, "Tweechies Own".! :-)

                                      73, Garey - K4OAH
                                      Glen Allen, VA

                                      Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                                      and TR-4/C Service Supplement CDs
                                      <www.k4oah.com>

                                      w6mqi wrote:
                                      > Dang I learn something everyday on Drake radio (Vaseline)I'm going to have to try this on my T4XB the problem child. I seem to remember with a C-line I had years ago I never had switch issues they would set idle for months without any switch contact issues at all. Now with my B-line the Deoxit is always on standby I guess once the oxidation process starts it's constant maintenance with these old boys.
                                      >
                                      > 73,Dave
                                      >
                                      >
                                      >
                                      > --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@...> wrote:
                                      >>
                                      >> ----- Original Message -----
                                      >> From: "William Houghton" <rdrbill@...>
                                      >> To: <DrakeRadio@yahoogroups.com>
                                      >> Sent: Wednesday, August 01, 2012 1:39 PM
                                      >> Subject: Re: [DrakeRadio] Re: T4XB Low Output
                                      >>
                                      >>
                                      >> Richard, et all,
                                      >>
                                      >> Is "Tuner-Lub" the product name ? Who is the mfgr?
                                      >>
                                      >> A couple of my Drakes that I have cleaned with DeOxit
                                      >> required 2 or 3
                                      >> treatments over a few weeks to get the problems solved. I
                                      >> used the 5% DeOxit not
                                      >> the 100%. The Caig datasheets that I saw for the 100% said
                                      >> you needed to clean
                                      >> it off after using. That wasn't required for the 5%. I have
                                      >> also noticed that if
                                      >> I don't use the gear for several weeks to months, I might
                                      >> have to re-treat it.
                                      >>
                                      >> I used No Al Ox on my tribander but I'd never use it on a
                                      >> wafer switch.
                                      >>
                                      >> Tunerlub is made by General Cement. I did a search for
                                      >> the MSDS, it turns out to be pure petrolatum, AKA, Vaseline
                                      >> with less than 20 PPM of BHT (butylated hydroxytoluene) in
                                      >> it. BHT us an anti-oxidant used in food packaging. Its
                                      >> probably there to prevent the stuff from turning brown. I
                                      >> think plain Vaseline would do as well.
                                      >>
                                      >>
                                    • Don Cunningham
                                      Garey, Some of the others may have made the mistake I did, I bought Deoxit D5, NOT the D100L as you did. I am wondering if the other solvents in my D5 might
                                      Message 18 of 25 , Aug 2, 2012
                                        Garey,
                                        Some of the others may have made the mistake I did, I bought Deoxit D5, NOT the D100L as you did. I am wondering if the "other" solvents in my D5 might be my problem, as I am facing the same need to re-do some of my earlier work.

                                        Just a thought, bite the bullet and get the "right stuff".
                                        73,
                                        Don, WB5HAK

                                        [Non-text portions of this message have been removed]
                                      • Garey Barrell
                                        Don - Possibly. I think D5 is more for new or nearly new contacts. It s only 5% DeoxIT , with the rest being various propellants and carrier. Assuming
                                        Message 19 of 25 , Aug 2, 2012
                                          Don -

                                          Possibly. I think D5 is more for 'new or nearly new' contacts. It's only 5% "DeoxIT", with the
                                          rest being various propellants and carrier. Assuming you mean the D5 spray, which is the most
                                          commonly available. I used to use D5 before I found D100L, and would spray some in the cap, let it
                                          sit for a few minutes, and then put it on with a dropper, brush or tweezers, whatever was handy. A
                                          useful applier is a paper clip straightened out with a tiny circle bent in the end.

                                          I just don't like sprays of any kind, with the exception of FaderLube to squirt inside pots.

                                          My point is that I only want to clean the contact area, leave the rest protected by the silver
                                          sulfide coating. D100L, applied to clean or nearly clean silver, seems to last forever. I go
                                          through a radio 'cleaning', then inspect for the bright line. If present I apply more D100 and
                                          leave it. If no bright line, but known silver contacts, try again. Only once do I recall having to
                                          go in with a Q-Tip, which came away green, indicating copper corrosion. The silver plating on
                                          switch contacts is very thin, and if 'cleaned' too thoroughly, especially with 'mechanical'
                                          cleaners, will go right down to the brass (copper) base metal.

                                          73, Garey - K4OAH
                                          Glen Allen, VA

                                          Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                                          and TR-4/C Service Supplement CDs
                                          <www.k4oah.com>

                                          Don Cunningham wrote:
                                          > Garey,
                                          > Some of the others may have made the mistake I did, I bought Deoxit D5, NOT the D100L as you did. I am wondering if the "other" solvents in my D5 might be my problem, as I am facing the same need to re-do some of my earlier work.
                                          >
                                          > Just a thought, bite the bullet and get the "right stuff".
                                          > 73,
                                          > Don, WB5HAK
                                          >
                                        • Tom
                                          I know it has been quite a while since I posted this topic but the problem is still there. I have determined that the problem is not in the function switch (I
                                          Message 20 of 25 , Jan 9, 2013
                                            I know it has been quite a while since I posted this topic but the problem is still there. I have determined that the problem is not in the function switch (I think). I will try again to describe the problem. When I first turn the transmitter on the output is very low. I turn the function switch to the x-cw position and back to tune and power output comes up. Over time it drifts down very slowly. If I rotate the switch a couple of times it comes back to full power. Then starts the slow drift back down. It acts as if something (cap?) is discharging. I have cleaned and rotated the switch many, many times. That's why I figure the problem is somewhere else. Don't get much use out of the rig brcause of this. Sure would like to make some progress so I will welcome any suggestions. Full output is around 120 watts and it drifts down to around 30 watts over time. HELP!! Thanks in advance.....Tom

                                            --- In DrakeRadio@yahoogroups.com, "Tom" wrote:
                                            >
                                            > Thanks Richard...We used to use a compound on high voltage connections that I think was call "No Al-Ox" or something similar to that. Mostly where aluminum wire was connected to any sort of copper. Sounds very much like what you bare referring to. Again..thanks to all. I at least now know where to go if and when the problem crops up.
                                            >
                                            > --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@> wrote:
                                            > >
                                            > >
                                            > > ----- Original Message -----
                                            > > From: "Tom"
                                            > > To:
                                            > > Sent: Wednesday, August 01, 2012 11:52 AM
                                            > > Subject: [DrakeRadio] Re: T4XB Low Output
                                            > >
                                            > >
                                            > > > Thanks very much for the replies. I cleaned the function
                                            > > > switch contacts the best I could and got the output up to
                                            > > > 120 watts. The next time I put it in tune, the output was
                                            > > > low again. Rock the switch and it comes back. Either I
                                            > > > have to clean it better or the contacts are shot. I think
                                            > > > I can probably work it out with a couple more cleanings.
                                            > > > I'm using regular contact cleaner. I should get some
                                            > > > DeOxit. I have never used it but seems to be the experts
                                            > > > choice. Thanks again...Tom
                                            > > >
                                            > >
                                            > > Don't trust the switch contacts to stay clean. Deoxit
                                            > > can work for a time but the pollutants in the air that
                                            > > corrode switch contacts is always there especially in
                                            > > cities. Caig Labs says that treating contacts with Deoxit
                                            > > Gold after cleaning with regular Deoxit will protect them.
                                            > > I have not tried this yet. However, I've had good success
                                            > > with Tuner-Lub, a light grease meant originally for TV
                                            > > tuners. I clean with Deoxit and when its evaporated put a
                                            > > little Tuner-Lub on with a toothpick or similar tool. I've
                                            > > treated switches that got flaky in a few days after cleaning
                                            > > with this stuff and it seems to prevent oxidation for months
                                            > > at least. I suspect that even Vaseline will work. Vaseline
                                            > > used to be the standard for treating contacts on bridges and
                                            > > resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                                            > > non-conducting and are easily cleaned off with naphtha.
                                            > > FWIW, the band switch in my TR-4 was persistently
                                            > > intermittent, not working at all on some bands until I
                                            > > cleaned the decks with Deoxit but would become intermittent
                                            > > again after a couple of days. Tuner-Lub after cleaning
                                            > > fixed this.
                                            > > I think this also has to do with the amount of pressure
                                            > > the spring contacts put on the wiper. I suspect its too low
                                            > > for the wiping action to be consistent in some switches. I
                                            > > don't have a fix for this other than perhaps replacing the
                                            > > switches but the above method seems to work at least for a
                                            > > reasonable time.
                                            > >
                                            > >
                                            > > --
                                            > > Richard Knoppow
                                            > > Los Angeles
                                            > > WB6KBL
                                            > > dickburk@
                                            > >
                                            >
                                          • Al Parker
                                            Hi Tom, I haven t been following your earlier thread, but see that it maybe focused on switch cleanliness. I d check the dropping resistor in the line to the
                                            Message 21 of 25 , Jan 9, 2013
                                              Hi Tom,
                                              I haven't been following your earlier thread, but see that it maybe
                                              focused on switch cleanliness.
                                              I'd check the dropping resistor in the line to the driver's plate, it's
                                              R-44 on the T4-XC, maybe same nr in the B. It may have drifted high in
                                              value and gotten more sensitive to heat, making it go higher. Similar
                                              on the screen resistor there, R-43. I've had that plate resistor cause
                                              a reduction in power in some that I've worked on.
                                              Also, I have the following in my archives, from K9JU in Nov. 2010:
                                              =================
                                              I've mentioned this before, rather recently, but check CR19 in the
                                              cathode circuit of the driver, V4 (12BY7). I have 2 T-4XC transmitters
                                              that exhibited sudden drop (to nothing in both cases) in power output.
                                              Both had CR19 with cracks in the cases. The diodes would appear OK with
                                              a DMM (diode mode) but with the application of heat would open up. Maybe
                                              there's some intermediate mode that would allow moderate output power
                                              but that doesn't seem to make too much sense. Most semiconductors work
                                              or they don't work, in my experience!
                                              A 1N4003 and up is good substitute for the B5G5 diode used by Drake.
                                              Bob K9JU
                                              =====================================

                                              I hope this will be a help to you.
                                              73,

                                              Al, W8UT
                                              www.boatanchors.org
                                              www.hammarlund.info

                                              "There is nothing -- absolutely nothing -- half so much
                                              worth doing as simply messing about in boats"
                                              Ratty, to Mole

                                              On 1/9/2013 5:48 PM, Tom wrote:
                                              > I know it has been quite a while since I posted this topic but the
                                              > problem is still there. I have determined that the problem is not in the
                                              > function switch (I think). I will try again to describe the problem.
                                              > When I first turn the transmitter on the output is very low. I turn the
                                              > function switch to the x-cw position and back to tune and power output
                                              > comes up. Over time it drifts down very slowly. If I rotate the switch a
                                              > couple of times it comes back to full power. Then starts the slow drift
                                              > back down. It acts as if something (cap?) is discharging. I have cleaned
                                              > and rotated the switch many, many times. That's why I figure the problem
                                              > is somewhere else. Don't get much use out of the rig brcause of this.
                                              > Sure would like to make some progress so I will welcome any suggestions.
                                              > Full output is around 120 watts and it drifts down to around 30 watts
                                              > over time. HELP!! Thanks in advance.....Tom
                                              >
                                            • Garey Barrell
                                              Tom - How long does it take to drift back down?? 73, Garey - K4OAH Glen Allen, VA Drake Service Supplement CDs for 2-B, 2-C/NT, A, B and C-Line, TR-4 and TR-4C
                                              Message 22 of 25 , Jan 9, 2013
                                                Tom -

                                                How long does it take to drift back down??

                                                73, Garey - K4OAH
                                                Glen Allen, VA
                                                Drake Service Supplement CDs for
                                                2-B, 2-C/NT, A, B and C-Line,
                                                TR-4 and TR-4C

                                                Tom wrote:
                                                > I know it has been quite a while since I posted this topic but the problem is still there. I have determined that the problem is not in the function switch (I think). I will try again to describe the problem. When I first turn the transmitter on the output is very low. I turn the function switch to the x-cw position and back to tune and power output comes up. Over time it drifts down very slowly. If I rotate the switch a couple of times it comes back to full power. Then starts the slow drift back down. It acts as if something (cap?) is discharging. I have cleaned and rotated the switch many, many times. That's why I figure the problem is somewhere else. Don't get much use out of the rig brcause of this. Sure would like to make some progress so I will welcome any suggestions. Full output is around 120 watts and it drifts down to around 30 watts over time. HELP!! Thanks in advance.....Tom
                                                >
                                                > --- In DrakeRadio@yahoogroups.com, "Tom" wrote:
                                                >> Thanks Richard...We used to use a compound on high voltage connections that I think was call "No Al-Ox" or something similar to that. Mostly where aluminum wire was connected to any sort of copper. Sounds very much like what you bare referring to. Again..thanks to all. I at least now know where to go if and when the problem crops up.
                                                >>
                                                >> --- In DrakeRadio@yahoogroups.com, "Richard Knoppow" <1oldlens1@> wrote:
                                                >>>
                                                >>> ----- Original Message -----
                                                >>> From: "Tom"
                                                >>> To:
                                                >>> Sent: Wednesday, August 01, 2012 11:52 AM
                                                >>> Subject: [DrakeRadio] Re: T4XB Low Output
                                                >>>
                                                >>>
                                                >>>> Thanks very much for the replies. I cleaned the function
                                                >>>> switch contacts the best I could and got the output up to
                                                >>>> 120 watts. The next time I put it in tune, the output was
                                                >>>> low again. Rock the switch and it comes back. Either I
                                                >>>> have to clean it better or the contacts are shot. I think
                                                >>>> I can probably work it out with a couple more cleanings.
                                                >>>> I'm using regular contact cleaner. I should get some
                                                >>>> DeOxit. I have never used it but seems to be the experts
                                                >>>> choice. Thanks again...Tom
                                                >>>>
                                                >>> Don't trust the switch contacts to stay clean. Deoxit
                                                >>> can work for a time but the pollutants in the air that
                                                >>> corrode switch contacts is always there especially in
                                                >>> cities. Caig Labs says that treating contacts with Deoxit
                                                >>> Gold after cleaning with regular Deoxit will protect them.
                                                >>> I have not tried this yet. However, I've had good success
                                                >>> with Tuner-Lub, a light grease meant originally for TV
                                                >>> tuners. I clean with Deoxit and when its evaporated put a
                                                >>> little Tuner-Lub on with a toothpick or similar tool. I've
                                                >>> treated switches that got flaky in a few days after cleaning
                                                >>> with this stuff and it seems to prevent oxidation for months
                                                >>> at least. I suspect that even Vaseline will work. Vaseline
                                                >>> used to be the standard for treating contacts on bridges and
                                                >>> resistance boxes, etc. Vaseline and Tuner-Lub seem to be
                                                >>> non-conducting and are easily cleaned off with naphtha.
                                                >>> FWIW, the band switch in my TR-4 was persistently
                                                >>> intermittent, not working at all on some bands until I
                                                >>> cleaned the decks with Deoxit but would become intermittent
                                                >>> again after a couple of days. Tuner-Lub after cleaning
                                                >>> fixed this.
                                                >>> I think this also has to do with the amount of pressure
                                                >>> the spring contacts put on the wiper. I suspect its too low
                                                >>> for the wiping action to be consistent in some switches. I
                                                >>> don't have a fix for this other than perhaps replacing the
                                                >>> switches but the above method seems to work at least for a
                                                >>> reasonable time.
                                                >>>
                                                >>>
                                                >>> --
                                                >>> Richard Knoppow
                                                >>> Los Angeles
                                                >>> WB6KBL
                                                >>> dickburk@
                                                >>>
                                                >
                                                >
                                                >
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                                              • Garey Barrell
                                                Tom - How long does it take to drift back down?? 73, Garey - K4OAH Glen Allen, VA Drake Service Supplement CDs for 2-B, 2-C/NT, A, B and C-Line, TR-4 and TR-4C
                                                Message 23 of 25 , Jan 10, 2013
                                                  Tom -

                                                  How long does it take to drift back down??

                                                  73, Garey - K4OAH
                                                  Glen Allen, VA
                                                  Drake Service Supplement CDs for
                                                  2-B, 2-C/NT, A, B and C-Line,
                                                  TR-4 and TR-4C

                                                  >>> From: "Tom"
                                                  >>> To:
                                                  >>> Sent: Wednesday, August 01, 2012 11:52 AM
                                                  >>> Subject: [DrakeRadio] Re: T4XB Low Output
                                                  >>>
                                                  >>>
                                                  >>>> Thanks very much for the replies. I cleaned the function
                                                  >>>> switch contacts the best I could and got the output up to
                                                  >>>> 120 watts. The next time I put it in tune, the output was
                                                  >>>> low again. Rock the switch and it comes back. Either I
                                                  >>>> have to clean it better or the contacts are shot. I think
                                                  >>>> I can probably work it out with a couple more cleanings.
                                                  >>>> I'm using regular contact cleaner. I should get some
                                                  >>>> DeOxit. I have never used it but seems to be the experts
                                                  >>>> choice. Thanks again...Tom
                                                  >>>>
                                                • Tom
                                                  Garey...Sorry this has taken so long. When first tuned the output is stable for 10-15 minutes then starts down very slowly. I keep checking every couple of
                                                  Message 24 of 25 , Feb 6, 2013
                                                    Garey...Sorry this has taken so long. When first tuned the output is stable for 10-15 minutes then starts down very slowly. I keep checking every couple of minutes so I think the problem is related to something heating up and changing value. I've been told there is a resistor in the PS section that supplies the voltage to unbalance the modulator to produce the carrier that goes through one section of the control pot. Not sure which one it is. Thanks....Tom

                                                    --- In DrakeRadio@yahoogroups.com, Garey Barrell wrote:
                                                    >
                                                    > Tom -
                                                    >
                                                    > How long does it take to drift back down??
                                                    >
                                                    > 73, Garey - K4OAH
                                                    > Glen Allen, VA
                                                    > Drake Service Supplement CDs for
                                                    > 2-B, 2-C/NT, A, B and C-Line,
                                                    > TR-4 and TR-4C
                                                    >
                                                    > >>> From: "Tom"
                                                    > >>> To:
                                                    > >>> Sent: Wednesday, August 01, 2012 11:52 AM
                                                    > >>> Subject: [DrakeRadio] Re: T4XB Low Output
                                                    > >>>
                                                    > >>>
                                                    > >>>> Thanks very much for the replies. I cleaned the function
                                                    > >>>> switch contacts the best I could and got the output up to
                                                    > >>>> 120 watts. The next time I put it in tune, the output was
                                                    > >>>> low again. Rock the switch and it comes back. Either I
                                                    > >>>> have to clean it better or the contacts are shot. I think
                                                    > >>>> I can probably work it out with a couple more cleanings.
                                                    > >>>> I'm using regular contact cleaner. I should get some
                                                    > >>>> DeOxit. I have never used it but seems to be the experts
                                                    > >>>> choice. Thanks again...Tom
                                                    > >>>>
                                                    >
                                                  • Garey Barrell
                                                    Tom - More likely that the finals are gassy. When the output is dropping, is the PLATE current dropping as well? After it s been running a while, and the
                                                    Message 25 of 25 , Feb 6, 2013
                                                      Tom -

                                                      More likely that the finals are gassy. When the output is dropping, is the PLATE current dropping
                                                      as well? After it's been running a while, and the output has dropped, check the idle current quickly.

                                                      Also check the value and condition of R26. Check R32, R33,these two should be within 5% of eachother.

                                                      R79 is the control for the unbalance of the BM. This is only used in CW to allow the CO to pass
                                                      through the BM. In TUNE mode, R84 controls the level of audio tone applied to the BM, which
                                                      generates a single frequency SSB signal (appears as a CW signal) for adjusting the amount of drive.

                                                      73, Garey - K4OAH
                                                      Glen Allen, VA

                                                      Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
                                                      and TR-4/C Service Supplement CDs
                                                      <www.k4oah.com>

                                                      Tom wrote:
                                                      > Garey...Sorry this has taken so long. When first tuned the output is stable for 10-15 minutes then starts down very slowly. I keep checking every couple of minutes so I think the problem is related to something heating up and changing value. I've been told there is a resistor in the PS section that supplies the voltage to unbalance the modulator to produce the carrier that goes through one section of the control pot. Not sure which one it is. Thanks....Tom
                                                      >
                                                      > --- In DrakeRadio@yahoogroups.com, Garey Barrell wrote:
                                                      >> Tom -
                                                      >>
                                                      >> How long does it take to drift back down??
                                                      >>
                                                      >> 73, Garey - K4OAH
                                                      >> Glen Allen, VA
                                                      >> Drake Service Supplement CDs for
                                                      >> 2-B, 2-C/NT, A, B and C-Line,
                                                      >> TR-4 and TR-4C
                                                      >>
                                                      >>>>> From: "Tom"
                                                      >>>>> To:
                                                      >>>>> Sent: Wednesday, August 01, 2012 11:52 AM
                                                      >>>>> Subject: [DrakeRadio] Re: T4XB Low Output
                                                      >>>>>
                                                      >>>>>
                                                      >>>>>> Thanks very much for the replies. I cleaned the function
                                                      >>>>>> switch contacts the best I could and got the output up to
                                                      >>>>>> 120 watts. The next time I put it in tune, the output was
                                                      >>>>>> low again. Rock the switch and it comes back. Either I
                                                      >>>>>> have to clean it better or the contacts are shot. I think
                                                      >>>>>> I can probably work it out with a couple more cleanings.
                                                      >>>>>> I'm using regular contact cleaner. I should get some
                                                      >>>>>> DeOxit. I have never used it but seems to be the experts
                                                      >>>>>> choice. Thanks again...Tom
                                                      >>>>>>
                                                      >
                                                      >
                                                      >
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