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power supply caps alternately smoking

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  • horsefly76
    Hello everyone New member with a question problem I have a softrock rxtx ensemble. After building the 1st stage power supply first 2 tests for 50k ohms and
    Message 1 of 20 , Sep 28, 2013
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      Hello everyone

      New member with a question problem

        I have  a softrock rxtx ensemble. After building the 1st stage power supply first 2 tests for 50k ohms and current draw go fine but when I go to do the final 12 volt/ 5 volt power check a different capacitor lets out the magic smoke?????? This has happened 2 times now I replace the bad and recheck each one of the 10 for faults and everything seams normal, any ideas? Everything installed by the book.

       Is not my first kit so I'm a bit corn fused. My 15 watt iron died so I have been using my 25 watt weller SP23L and I think it may be too much heat for the little caps.

      Any help/ ideas?

      Thanks!
      Aaron.  N7UAV
    • Paul Playford
      Check the polarity of the capacitors as you install them. They will self destruct if in backward. de Paul, W8AEF From: slickjimmy76@gmail.com Sent: Saturday,
      Message 2 of 20 , Sep 28, 2013
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        Check the polarity of the capacitors as you install them.
         
        They will self destruct if in backward.
         
        de Paul, W8AEF
         
        Sent: Saturday, September 28, 2013 6:55 PM
        Subject: [softrock40] power supply caps alternately smoking
         
         

        Hello everyone

        New member with a question problem

          I have  a softrock rxtx ensemble. After building the 1st stage power supply first 2 tests for 50k ohms and current draw go fine but when I go to do the final 12 volt/ 5 volt power check a different capacitor lets out the magic smoke?????? This has happened 2 times now I replace the bad and recheck each one of the 10 for faults and everything seams normal, any ideas? Everything installed by the book.

        Is not my first kit so I'm a bit corn fused. My 15 watt iron died so I have been using my 25 watt weller SP23L and I think it may be too much heat for the little caps.

        Any help/ ideas?

        Thanks!
        Aaron.  N7UAV

      • horsefly76
        Thanks paul, polarity is ok. I m pretty shure I cooked them using my 25w iron (my 15w had just died). I have bought a new 12w weller pencil iron today & sent
        Message 3 of 20 , Sep 28, 2013
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          Thanks paul, polarity is ok. I'm pretty shure I cooked them using my 25w iron (my 15w had just died). I have bought a new 12w weller pencil iron today & sent an e mail to Tony about getting some more 10uf caps. Rs & my local ham radio/electronics stores did not have the right caps :/
        • cbayona
          To cook a cap with the soldering iron takes extra effort or a poor tool, how long do you put the soldering iron against the joint? The soldering iron is a most
          Message 4 of 20 , Sep 29, 2013
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            To cook a cap with the soldering iron takes extra effort or a poor
            tool, how long do you put the soldering iron against the joint?

            The soldering iron is a most important tool, buying a cheap one is
            false economy, besides one can buy a fairly good temperature
            controlled iron for under $40 and it will last you a lifetime. I use
            a Solomon SR-976 it's sold under various brand names it's heating
            element is a 48 watts quick heating ceramic heater. It maintains a
            constant temperature and goes from dead cold to ready to use in under
            5 seconds. I have two of them, the original one is over 15 years old
            and still has the original tip because a temperature controlled
            soldering iron does not allow the tip to get any hotter (which
            damages the tip) than the set temperature unlike a simple dumb iron.
            With it soldering a joint is a less than two second affair.

            This is where I bought mine many years ago so you can get an idea of
            what are the features of a temperature controlled iron, I still see
            them in other places for $35. This is by no means the only iron of
            it's kind, Weller, and Hakko are other well know brands.

            <
            <http://www.circuitspecialists.com/sr-976n-solder-station.html>http://www.circuitspecialists.com/sr-976n-solder-station.html
            >


            At 01:35 AM 9/29/2013, you wrote:


            >Thanks paul, polarity is ok. I'm pretty shure I cooked them using my
            >25w iron (my 15w had just died). I have bought a new 12w weller
            >pencil iron today & sent an e mail to Tony about getting some more
            >10uf caps. Rs & my local ham radio/electronics stores did not have
            >the right caps :/

            --
            Cecil - k5nwa
            < http://thepartsplace.k5nwa.com/ > < http://www.softrockradio.org/ >

            Never take life seriously. Nobody gets out alive anyway.
          • Zack Widup
            I have never destroyed a device with heat by soldering it or heating it with a heat gun. Never. I would really suspect the polarity. I ve noticed on a few caps
            Message 5 of 20 , Sep 29, 2013
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              I have never destroyed a device with heat by soldering it or heating
              it with a heat gun. Never. I would really suspect the polarity. I've
              noticed on a few caps I've purchased that for some reason they put the
              band on the negative end. It usually goes on the positive end. But the
              data sheet for that particular part says so. The only other reason
              would be a voltage beyond the rating of the cap.

              73, Zack W9SZ

              On 9/29/13, slickjimmy76@... <slickjimmy76@...> wrote:
              >
              >
              > Thanks paul, polarity is ok. I'm pretty shure I cooked them using my 25w
              > iron (my 15w had just died). I have bought a new 12w weller pencil iron
              > today sent an e mail to Tony about getting some more 10uf caps. Rs my local
              > ham radio/electronics stores did not have the right caps :/
              >
              >
            • Paul Playford
              Ah youth. Electrolytic capacitors have always had the band on the negative end. Tantalum capacitors have their band on the positive end. Just to keep life
              Message 6 of 20 , Sep 29, 2013
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                Ah youth. Electrolytic capacitors have always had the band on the negative
                end.

                Tantalum capacitors have their band on the positive end.

                Just to keep life interesting.

                de Paul, W8AEF

                -----Original Message-----
                From: Zack Widup
                Sent: Sunday, September 29, 2013 10:20 AM
                To: softrock40@yahoogroups.com
                Subject: Re: [softrock40] RE: power supply caps alternately smoking

                I have never destroyed a device with heat by soldering it or heating
                it with a heat gun. Never. I would really suspect the polarity. I've
                noticed on a few caps I've purchased that for some reason they put the
                band on the negative end. It usually goes on the positive end. But the
                data sheet for that particular part says so. The only other reason
                would be a voltage beyond the rating of the cap.

                73, Zack W9SZ
              • Chris Wilson
                ... 29/09/2013 20:34 I learn something from this forum every day! Noted, it is a bit like Jaguar having the number one designated cylinder at the back, by the
                Message 7 of 20 , Sep 29, 2013
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                  > Ah youth. Electrolytic capacitors have always had the band on the negative
                  > end.

                  > Tantalum capacitors have their band on the positive end.

                  > Just to keep life interesting.

                  > de Paul, W8AEF



                  29/09/2013 20:34

                  I learn something from this forum every day! Noted, it is a bit like
                  Jaguar having the number one designated cylinder at the back, by the
                  bulkhead, on their early straight six engines, just to confuse people
                  timing them up :)

                  --
                  Best Regards,
                  Chris Wilson. 2E0ILY
                • horsefly76
                  Band on - side also marked with a - sign along the band. The long leg + side unmarked. I have pictures to prove it lol as I took a few during the build for
                  Message 8 of 20 , Sep 29, 2013
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                     Band on - side also marked with a - sign along the band.  The long leg + side unmarked. I have pictures to prove it lol as I took a few during the build for reference. 


                    Gotta go stakes on the grill! :)


                    Aaron.



                    ---In softrock40@yahoogroups.com, <chris@...> wrote:

                    > Ah youth. Electrolytic capacitors have always had the band on the negative
                    > end.

                    > Tantalum capacitors have their band on the positive end.

                    > Just to keep life interesting.

                    > de Paul, W8AEF



                    29/09/2013 20:34

                    I learn something from this forum every day! Noted, it is a bit like
                    Jaguar having the number one designated cylinder at the back, by the
                    bulkhead, on their early straight six engines, just to confuse people
                    timing them up :)

                    --
                    Best Regards,
                    Chris Wilson. 2E0ILY
                  • Zack Widup
                    All the surface-mount electrolytics I use must be tantalums. They all have the positive side marked with a band. Youth? I ve been a licensed ham since 1967.
                    Message 9 of 20 , Sep 29, 2013
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                      All the surface-mount electrolytics I use must be tantalums. They all
                      have the positive side marked with a band.

                      Youth? I've been a licensed ham since 1967. Been building electronics
                      since before that. I worked in an electronics repair shop for 15
                      years. Most of my own construction work is surface-mount these days.
                      Just finished designing and building a board for an LNDFS circuit that
                      will be the LO for a 47 GHz transverter. Looks good so far. Still have
                      to multiply the 159 MHz frequency by 288. :-)

                      73, Zack W9SZ

                      On 9/29/13, Paul Playford <w8aef@...> wrote:
                      > Ah youth. Electrolytic capacitors have always had the band on the negative
                      >
                      > end.
                      >
                      > Tantalum capacitors have their band on the positive end.
                      >
                      > Just to keep life interesting.
                      >
                      > de Paul, W8AEF
                      >
                      > -----Original Message-----
                      > From: Zack Widup
                      > Sent: Sunday, September 29, 2013 10:20 AM
                      > To: softrock40@yahoogroups.com
                      > Subject: Re: [softrock40] RE: power supply caps alternately smoking
                      >
                      > I have never destroyed a device with heat by soldering it or heating
                      > it with a heat gun. Never. I would really suspect the polarity. I've
                      > noticed on a few caps I've purchased that for some reason they put the
                      > band on the negative end. It usually goes on the positive end. But the
                      > data sheet for that particular part says so. The only other reason
                      > would be a voltage beyond the rating of the cap.
                      >
                      > 73, Zack W9SZ
                      >
                      >
                      >
                      > ------------------------------------
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                    • Richard Mogford
                      Hi Does anyone know anything about the UPS2SDR board and its availability? Richard From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On
                      Message 10 of 20 , Sep 29, 2013
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                        Hi

                         

                        Does anyone know anything about the UPS2SDR  board and its availability?

                         

                        Richard

                         

                        From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of Zack Widup
                        Sent: Sunday, September 29, 2013 10:58 PM
                        To: softrock40@yahoogroups.com
                        Subject: Re: [softrock40] RE: power supply caps alternately smoking

                         

                         

                        All the surface-mount electrolytics I use must be tantalums. They all
                        have the positive side marked with a band.

                        Youth? I've been a licensed ham since 1967. Been building electronics
                        since before that. I worked in an electronics repair shop for 15
                        years. Most of my own construction work is surface-mount these days.
                        Just finished designing and building a board for an LNDFS circuit that
                        will be the LO for a 47 GHz transverter. Looks good so far. Still have
                        to multiply the 159 MHz frequency by 288. :-)

                        73, Zack W9SZ

                        On 9/29/13, Paul Playford <w8aef@...> wrote:
                        > Ah youth. Electrolytic capacitors have always had the band on the negative
                        >
                        > end.
                        >
                        > Tantalum capacitors have their band on the positive end.
                        >
                        > Just to keep life interesting.
                        >
                        > de Paul, W8AEF
                        >
                        > -----Original Message-----
                        > From: Zack Widup
                        > Sent: Sunday, September 29, 2013 10:20 AM
                        > To: softrock40@yahoogroups.com
                        > Subject: Re: [softrock40] RE: power supply caps alternately smoking
                        >
                        > I have never destroyed a device with heat by soldering it or heating
                        > it with a heat gun. Never. I would really suspect the polarity. I've
                        > noticed on a few caps I've purchased that for some reason they put the
                        > band on the negative end. It usually goes on the positive end. But the
                        > data sheet for that particular part says so. The only other reason
                        > would be a voltage beyond the rating of the cap.
                        >
                        > 73, Zack W9SZ
                        >
                        >
                        >
                        > ------------------------------------
                        >
                        > Yahoo! Groups Links
                        >
                        >
                        >
                        >

                      • Doug Luurs
                        Stakes ?? I hope you’re not planning to use those on any vampires *Grins* Doug From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On
                        Message 11 of 20 , Sep 30, 2013
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                          Stakes ??  I hope you’re not planning to use those on any vampires *Grins*

                           

                          Doug

                           

                          From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of slickjimmy76@...
                          Sent: Sunday, September 29, 2013 9:20 PM
                          To: softrock40@yahoogroups.com
                          Subject: [softrock40] RE: power supply caps alternately smoking

                           

                           

                           Band on - side also marked with a - sign along the band.  The long leg + side unmarked. I have pictures to prove it lol as I took a few during the build for reference. 

                           

                          Gotta go stakes on the grill! :)

                           

                          Aaron.



                          ---In softrock40@yahoogroups.com, <chris@...> wrote:

                          > Ah youth. Electrolytic capacitors have always had the band on the negative
                          > end.

                          > Tantalum capacitors have their band on the positive end.

                          > Just to keep life interesting.

                          > de Paul, W8AEF




                          29/09/2013 20:34

                          I learn something from this forum every day! Noted, it is a bit like
                          Jaguar having the number one designated cylinder at the back, by the
                          bulkhead, on their early straight six engines, just to confuse people
                          timing them up :)

                          --
                          Best Regards,
                          Chris Wilson. 2E0ILY

                        • Chris Wilson
                          ... 30/09/2013 12:22 This steak s like a piece of board :) -- Best Regards, Chris Wilson. 2E0ILY
                          Message 12 of 20 , Sep 30, 2013
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                            >

                            > Stakes ?? I hope you’re not planning to use those on any vampires *Grins*
                            >
                            > Doug
                            >


                            30/09/2013 12:22


                            "This steak's like a piece of board" :)


                            --
                            Best Regards,
                            Chris Wilson. 2E0ILY
                          • Brad Thompson
                            ... Hello, Zack and the group-- Zack, you no doubt already know about this but some of the group s newcomers may not. If there s any doubt, connect a
                            Message 13 of 20 , Sep 30, 2013
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                              On 9/30/2013 1:58 AM, Zack Widup wrote:
                              > All the surface-mount electrolytics I use must be tantalums. They all
                              > have the positive side marked with a band.
                              >
                              <snip>

                              Hello, Zack and the group--

                              Zack, you no doubt already know about this but some of the
                              group's newcomers may not.

                              If there's any doubt, connect a resistor (say, 10 ohms at 1/4 watt)
                              in series with the purported positive terminal and then
                              connect the series network across a power supply set to the
                              capacitor's rated voltage (network plus to plus, minus to minus).

                              If the capacitor and/or resistor smoke, the assumed polarity is
                              incorrect.

                              For further reassurance, identify the capacitor's manufacturer and
                              consult the part's data sheet.

                              Your for creative smoke testing, and 73--

                              Brad AA1IP
                            • horsefly76
                              Ya that s what I get for using my smart phone, it auto corrects everything I type. I had to teach it steak just now lol
                              Message 14 of 20 , Sep 30, 2013
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                                Ya that's what I get for using my "smart" phone, it auto corrects everything I type. I had to teach it "steak" just now lol
                              • John Rabson
                                ... Better than some dictation software. I once did the publicity for a village party, and bring a dish came out as bring a geisha . John
                                Message 15 of 20 , Sep 30, 2013
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                                  On 30 Sep 2013, at 16:18CEST, <slickjimmy76@...> <slickjimmy76@...> wrote:

                                  > Ya that's what I get for using my "smart" phone, it auto corrects everything I type. I had to teach it "steak" just now lol

                                  Better than some dictation software. I once did the publicity for a village party, and "bring a dish" came out as "bring a geisha".

                                  John
                                • Peter Johnson
                                  Hi John. Bet you had a good turnout. Regards Peter F1VKK
                                  Message 16 of 20 , Sep 30, 2013
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                                    Hi John.

                                    Bet you had a good turnout.

                                    Regards Peter F1VKK



                                    On 30/09/2013 16:31, John Rabson wrote:
                                    > On 30 Sep 2013, at 16:18CEST, <slickjimmy76@...> <slickjimmy76@...> wrote:
                                    >
                                    >> Ya that's what I get for using my "smart" phone, it auto corrects everything I type. I had to teach it "steak" just now lol
                                    > Better than some dictation software. I once did the publicity for a village party, and "bring a dish" came out as "bring a geisha".
                                    >
                                    > John
                                  • horsefly76
                                    Tony is sending me 10 more caps free of charge :) I offered to pay but Tony would have none of that. Wont be able to finish till next weekend as I m at work 11
                                    Message 17 of 20 , Sep 30, 2013
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                                      Tony is sending me 10 more caps free of charge :) I offered to pay but Tony would have none of that. Wont be able to finish till next weekend as I'm at work 11 to 13 hrs a day.
                                    • horsefly76
                                      Tony is sending me 10 more caps free of charge :) I offered to pay but Tony would have none of that. Wont be able to finish till next weekend as I m at work 11
                                      Message 18 of 20 , Sep 30, 2013
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                                        Tony is sending me 10 more caps free of charge :) I offered to pay but Tony would have none of that. Wont be able to finish till next weekend as I'm at work 11 to 13 hrs a day.
                                      • horsefly76
                                        I did find one small discrepancy with C 23. silk screening on my board does not match the completed assembly picture in the manual. I emailed Tony and he said
                                        Message 19 of 20 , Oct 1, 2013
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                                          I did find one small discrepancy with C 23. silk screening on my board does not match the completed assembly picture in the manual. I emailed Tony and he said to go by he silk screening on the board/schematic & not the picture. The picture in the assembly drawing was for a different board. Thank you Tony & the fourm here for your help so far, I'm shure I will have many more questions.
                                        • Zack Widup
                                          Yes, I do that quite a bit. Very similar to the trick I learned years ago with AC-powered solid-state audio amps. Often the output and driver transistors and
                                          Message 20 of 20 , Oct 2, 2013
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                                            Yes, I do that quite a bit. Very similar to the trick I learned years
                                            ago with AC-powered solid-state audio amps. Often the output and
                                            driver transistors and other transistors will go bad by shorting out.
                                            After replacing all the ones you think are bad, you may miss one or
                                            two. This will probably cause a short to still present itself to the
                                            AC line input. Instead of going through half a box of fuses and
                                            possibly damaging more parts, use a 75 or 100 watt incandescent light
                                            bulb in series with the 110 volts AC. If, when turning on the circuit,
                                            the bulb glows brightly for a second and then diminishes as the power
                                            supply capacitors charge up, everything is OK and you can remove the
                                            bulb from the circuit. If the bulb remains fully brightly lit, you
                                            still have a problem. I've used this technique countless times.

                                            It wasn't clear to me what kind of capacitors were smoking. If they
                                            were the radial-leaded type, the band is on the negative end. I've had
                                            tantalum surface-mount caps in backwards, too. They will also get
                                            extremely hot and smoke, or maybe even just blow off the board.
                                            Sometimes taking part of the board with them. :-(

                                            73, Zack W9SZ


                                            On 9/30/13, Brad Thompson <brad.thompson@...> wrote:
                                            > On 9/30/2013 1:58 AM, Zack Widup wrote:
                                            >> All the surface-mount electrolytics I use must be tantalums. They all
                                            >> have the positive side marked with a band.
                                            >>
                                            > <snip>
                                            >
                                            > Hello, Zack and the group--
                                            >
                                            > Zack, you no doubt already know about this but some of the
                                            > group's newcomers may not.
                                            >
                                            > If there's any doubt, connect a resistor (say, 10 ohms at 1/4 watt)
                                            > in series with the purported positive terminal and then
                                            > connect the series network across a power supply set to the
                                            > capacitor's rated voltage (network plus to plus, minus to minus).
                                            >
                                            > If the capacitor and/or resistor smoke, the assumed polarity is
                                            > incorrect.
                                            >
                                            > For further reassurance, identify the capacitor's manufacturer and
                                            > consult the part's data sheet.
                                            >
                                            > Your for creative smoke testing, and 73--
                                            >
                                            > Brad AA1IP
                                            >
                                            >
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