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Re: Need advice for repairing Organ (mostly capacitors)

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  • MUSIBIKE@juno.com
    I was an organ repair person at a music store here in Houston. Seen a good many like this one. That one was most likely made in the late to mid 60 s? I have an
    Message 1 of 10 , Jan 1, 2004
      I was an organ repair person at a music store here in Houston. Seen a
      good many like this one.

      That one was most likely made in the late to mid 60's? I have an old
      Thomas organ that the store gave me. The wife loves it.

      Verify that the LESLIE is not constantly spinning. There might be some
      loose junk like dead roaches and maybe even a mouse skeleton rattling
      around in there. The fist thing is to UNPLUG it and clean out the obvious.

      Pull out the power supply amplifer subassembly and check all of the
      old electrolytics and see if there is anything coming out of the
      transformer like tar. Sometimes those get a shortwed turn in them and
      there is no salvatuion for them. You have to rig something else. But,
      that is all doable.

      Every city has music stores where Church organs are sold and
      supported. Get yourself a manual on the unit if you are not too
      familar with them.

      A lot of those older transistors will survive what you have sated
      above because those older circuits limit the short circuit currents
      going to them. But, in the power amp or REVERB section maybe not.

      I would get a variac and bring the organ to a reduced input power
      voltage of about half to start with. The capacitors must rejuvinate
      their electrolytes if they have not been used for a good while. Watch
      to see that things don't smoke out though. Take a voltmeter and see
      what happens across caps over a few minutes to see if these recover.
      You will have to replace the cracked ones for sure.

      I can post a capacitor color code in the photos section.

      MUSIBIKE

      --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...> wrote:
      > I just bought an old transistorized combo organ. When I plugged it
      > in and turned it on, I heard a number of small "tinkling"
      > and "ticking" sounds from inside the case. Dispite this, the organ
      > played reasonably well, although it was quite out of tune
      > and "scratchy" sounding. After being turned on for about 15 minutes,
      > white smoke and a burning plastic smell started coming out of the
      > case. I switched it off and eventually the smoke dissapated. After
      > taking the case off, I could see that the wires coming off the
      > transformer to the filter caps were melted where they touched the
      > transformer (it was quite hot).
      >
      > After doing some investigation, I found two things wrong with the
      > circuitry. First, a number of the capacitors were cracked (not the
      > electrolytics), some of them so badly as to lose parts of their
      > coatings. Also, some of the transistors "legs" were touching each-
      > other. I suspect that the sounds I heard were the capacitors
      > cracking. The electrolytics all seem to be fine, but most of the
      > dipped ones with color bands on them seem to be bad, and many of the
      > solid brown ones (ceramic?) look to be bad as well.
      >
      > That leaves me with a few questions. Are these "solid" capacitors
      > prone to cracking, and can they be replaced with modern equivalents?
      > How do I read these color stripes for values, ratings, etc.? Most of
      > the sources I've looked at don't say which direction you read from
      > (the top end or the wired end), nor do they say what color they are
      > underneath it all (most of them seem to have sort of mustard-colored
      > bottoms).
      >
      > And, if the transistors wires were touching when it was turned on, is
      > it likely that the transistors have been terminally damaged and need
      > replacement? It's worth it to me to repair this organ, as it's quite
      > rare and I've been looking for one for a long time.
      >
      > Thanks in advance for any advice.
      >
      > -- Robert
    • Michael Casino
      Robert: Which combo organ are you referring to ? There is a combo organ group or two in the yahoo groups. www.combo-oegan.com
      Message 2 of 10 , Jan 1, 2004
        Robert:
         
        Which combo organ are you referring to ?
         
        There is a combo organ group or two in the yahoo groups.
         
         
        Mike Casino
         
        <snip>
         
        I just bought an old transistorized combo organ.
        <snip> 
        as it's quite rare and I've been looking for one for a long time. 
        Thanks in advance for any advice. 
        -- Robert
      • Robert
        Hi Mike -- Thanks for thinking of the Combo Organ Yahoo!Group. I m a member, and they re a helpful bunch, but I thought the questions I posed here were more
        Message 3 of 10 , Jan 1, 2004
          Hi Mike --

          Thanks for thinking of the Combo Organ Yahoo!Group. I'm a member,
          and they're a helpful bunch, but I thought the questions I posed here
          were more specifically appropriate to this group. I may end up
          posting the same questions there.

          Cheers --

          Robert




          --- In Electronics_101@yahoogroups.com, "Michael Casino"
          <mtcasino@c...> wrote:
          > Robert:
          >
          > Which combo organ are you referring to ?
          >
          > There is a combo organ group or two in the yahoo groups.
          >
          > www.combo-oegan.com
          > http://groups.yahoo.com/group/ComboOrgan
          >
          > Mike Casino
          >
          > <snip>
          >
          > I just bought an old transistorized combo organ.
          > <snip>
          > as it's quite rare and I've been looking for one for a long time.
          > Thanks in advance for any advice.
          > -- Robert
        • Robert
          Oops -- its an Italian-made Cordovox from the late- 60s-early- 70s. You may have seen them before; they re pretty distinctive with their space-age, one-piece
          Message 4 of 10 , Jan 1, 2004
            Oops -- its an Italian-made Cordovox from the late-'60s-early-'70s.
            You may have seen them before; they're pretty distinctive with their
            space-age, one-piece white fiberglass cases. Sometimes referred to
            as the "white elephant".

            -- Robert



            --- In Electronics_101@yahoogroups.com, "Michael Casino"
            <mtcasino@c...> wrote:
            > Robert:
            >
            > Which combo organ are you referring to ?
          • Robert
            Hi Musibike -- Thanks very much for the advice. The organ was made sometime in the late- 60s to early- 70s, by an Italian company. This one doesn t have a
            Message 5 of 10 , Jan 1, 2004
              Hi "Musibike" --

              Thanks very much for the advice. The organ was made sometime in the
              late-'60s to early-'70s, by an Italian company. This one doesn't
              have a Leslie, so at least we can rule that out. All of the
              electrolytics look clean and not deformed to me. I should've brought
              it up on a variac, but I was too excited and impatient, and I
              suspected that it had been damaged in shipping (you wouldn't BELIEVE
              how poorly packed it was, and the case was cracked during transit),
              so I just spaced on that. I'll pull the transformer and check it
              out.

              Since the ceramic (?) caps that are cracked are mounted on PCBs, I
              presume that I need to remove the PCBs to get to the back sides, so I
              can melt the solder to get them out. Am I correct in assuming that I
              don't need to use heatsinks when soldering on a PCB, just a low-
              wattage soldering pencil?

              Also, I've seen some color codes for caps and am trying to memorize
              them, but the two things that I have never seen explained is which
              end you read from--the end with the wires or the top end, and what
              the base color of them is. Some of these caps look to be entirely
              covered with color stripes, but on some, it looks like the cap itself
              is a sort of mustard color, although that may be another color.

              I think I'm dealing with two different kinds of caps here, and I want
              to make sure I'm describing them correctly. The kind that have
              stripes are irregular rectangles with rounded corners. They look
              like they were formed by dipping into some material. The surface is
              quite smooth and shiny. The other kind I described have numbers
              printed on them. They are a solid brown color, more like irregular
              cylinders and have a matte finish--rather like terra-cotta. If I
              knew what to properly call these, it would help.

              Thanks again --

              Robert




              --- In Electronics_101@yahoogroups.com, MUSIBIKE@j... wrote:
              > I was an organ repair person at a music store here in Houston. Seen
              a
              > good many like this one.
              >
              > That one was most likely made in the late to mid 60's? I have an old
              > Thomas organ that the store gave me. The wife loves it.
              >
              > Verify that the LESLIE is not constantly spinning. There might be
              some
              > loose junk like dead roaches and maybe even a mouse skeleton
              rattling
              > around in there. The fist thing is to UNPLUG it and clean out the
              obvious.
              >
              > Pull out the power supply amplifer subassembly and check all of the
              > old electrolytics and see if there is anything coming out of the
              > transformer like tar. Sometimes those get a shortwed turn in them
              and
              > there is no salvatuion for them. You have to rig something else.
              But,
              > that is all doable.
              >
              > Every city has music stores where Church organs are sold and
              > supported. Get yourself a manual on the unit if you are not too
              > familar with them.
              >
              > A lot of those older transistors will survive what you have sated
              > above because those older circuits limit the short circuit currents
              > going to them. But, in the power amp or REVERB section maybe not.
              >
              > I would get a variac and bring the organ to a reduced input power
              > voltage of about half to start with. The capacitors must rejuvinate
              > their electrolytes if they have not been used for a good while.
              Watch
              > to see that things don't smoke out though. Take a voltmeter and see
              > what happens across caps over a few minutes to see if these recover.
              > You will have to replace the cracked ones for sure.
              >
              > I can post a capacitor color code in the photos section.
              >
              > MUSIBIKE
              >
              > --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...>
              wrote:
              > > I just bought an old transistorized combo organ. When I plugged
              it
              > > in and turned it on, I heard a number of small "tinkling"
              > > and "ticking" sounds from inside the case. Dispite this, the
              organ
              > > played reasonably well, although it was quite out of tune
              > > and "scratchy" sounding. After being turned on for about 15
              minutes,
              > > white smoke and a burning plastic smell started coming out of the
              > > case. I switched it off and eventually the smoke dissapated.
              After
              > > taking the case off, I could see that the wires coming off the
              > > transformer to the filter caps were melted where they touched the
              > > transformer (it was quite hot).
              > >
              > > After doing some investigation, I found two things wrong with the
              > > circuitry. First, a number of the capacitors were cracked (not
              the
              > > electrolytics), some of them so badly as to lose parts of their
              > > coatings. Also, some of the transistors "legs" were touching
              each-
              > > other. I suspect that the sounds I heard were the capacitors
              > > cracking. The electrolytics all seem to be fine, but most of the
              > > dipped ones with color bands on them seem to be bad, and many of
              the
              > > solid brown ones (ceramic?) look to be bad as well.
              > >
              > > That leaves me with a few questions. Are these "solid"
              capacitors
              > > prone to cracking, and can they be replaced with modern
              equivalents?
              > > How do I read these color stripes for values, ratings, etc.?
              Most of
              > > the sources I've looked at don't say which direction you read
              from
              > > (the top end or the wired end), nor do they say what color they
              are
              > > underneath it all (most of them seem to have sort of mustard-
              colored
              > > bottoms).
              > >
              > > And, if the transistors wires were touching when it was turned
              on, is
              > > it likely that the transistors have been terminally damaged and
              need
              > > replacement? It's worth it to me to repair this organ, as it's
              quite
              > > rare and I've been looking for one for a long time.
              > >
              > > Thanks in advance for any advice.
              > >
              > > -- Robert
            • MUSIBIKE@juno.com
              I have several capacitor catalogs at work. Will be there tomorrow. I can get you the phone numbers and LINKs for them. They will provide you FREE catalogs and
              Message 6 of 10 , Jan 1, 2004
                I have several capacitor catalogs at work. Will be there tomorrow. I
                can get you the phone numbers and LINKs for them. They will provide
                you FREE catalogs and help. They want to sell you CAPACITORS. The same
                is true for any semiconductor like older transistors. I have worked on
                a couple of those old things. All ANALOG. No sampling, simple.

                I think the new KEYBOARDS are way over teched these days. Not fixable
                without a programmer and specialized soldering tools.

                All you need to fix that one you have there is common sense and a
                30watt iron.

                Send you the Capacitor info tomorrow at work.

                MUSIBIKE

                --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...> wrote:
                > Hi "Musibike" --
                >
                > Thanks very much for the advice. The organ was made sometime in the
                > late-'60s to early-'70s, by an Italian company. This one doesn't
                > have a Leslie, so at least we can rule that out. All of the
                > electrolytics look clean and not deformed to me. I should've brought
                > it up on a variac, but I was too excited and impatient, and I
                > suspected that it had been damaged in shipping (you wouldn't BELIEVE
                > how poorly packed it was, and the case was cracked during transit),
                > so I just spaced on that. I'll pull the transformer and check it
                > out.
                >
                > Since the ceramic (?) caps that are cracked are mounted on PCBs, I
                > presume that I need to remove the PCBs to get to the back sides, so I
                > can melt the solder to get them out. Am I correct in assuming that I
                > don't need to use heatsinks when soldering on a PCB, just a low-
                > wattage soldering pencil?
                >
                > Also, I've seen some color codes for caps and am trying to memorize
                > them, but the two things that I have never seen explained is which
                > end you read from--the end with the wires or the top end, and what
                > the base color of them is. Some of these caps look to be entirely
                > covered with color stripes, but on some, it looks like the cap itself
                > is a sort of mustard color, although that may be another color.
                >
                > I think I'm dealing with two different kinds of caps here, and I want
                > to make sure I'm describing them correctly. The kind that have
                > stripes are irregular rectangles with rounded corners. They look
                > like they were formed by dipping into some material. The surface is
                > quite smooth and shiny. The other kind I described have numbers
                > printed on them. They are a solid brown color, more like irregular
                > cylinders and have a matte finish--rather like terra-cotta. If I
                > knew what to properly call these, it would help.
                >
                > Thanks again --
                >
                > Robert
                >
                >
                >
                >
                > --- In Electronics_101@yahoogroups.com, MUSIBIKE@j... wrote:
                > > I was an organ repair person at a music store here in Houston. Seen
                > a
                > > good many like this one.
                > >
                > > That one was most likely made in the late to mid 60's? I have an old
                > > Thomas organ that the store gave me. The wife loves it.
                > >
                > > Verify that the LESLIE is not constantly spinning. There might be
                > some
                > > loose junk like dead roaches and maybe even a mouse skeleton
                > rattling
                > > around in there. The fist thing is to UNPLUG it and clean out the
                > obvious.
                > >
                > > Pull out the power supply amplifer subassembly and check all of the
                > > old electrolytics and see if there is anything coming out of the
                > > transformer like tar. Sometimes those get a shortwed turn in them
                > and
                > > there is no salvatuion for them. You have to rig something else.
                > But,
                > > that is all doable.
                > >
                > > Every city has music stores where Church organs are sold and
                > > supported. Get yourself a manual on the unit if you are not too
                > > familar with them.
                > >
                > > A lot of those older transistors will survive what you have sated
                > > above because those older circuits limit the short circuit currents
                > > going to them. But, in the power amp or REVERB section maybe not.
                > >
                > > I would get a variac and bring the organ to a reduced input power
                > > voltage of about half to start with. The capacitors must rejuvinate
                > > their electrolytes if they have not been used for a good while.
                > Watch
                > > to see that things don't smoke out though. Take a voltmeter and see
                > > what happens across caps over a few minutes to see if these recover.
                > > You will have to replace the cracked ones for sure.
                > >
                > > I can post a capacitor color code in the photos section.
                > >
                > > MUSIBIKE
                > >
                > > --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...>
                > wrote:
                > > > I just bought an old transistorized combo organ. When I plugged
                > it
                > > > in and turned it on, I heard a number of small "tinkling"
                > > > and "ticking" sounds from inside the case. Dispite this, the
                > organ
                > > > played reasonably well, although it was quite out of tune
                > > > and "scratchy" sounding. After being turned on for about 15
                > minutes,
                > > > white smoke and a burning plastic smell started coming out of the
                > > > case. I switched it off and eventually the smoke dissapated.
                > After
                > > > taking the case off, I could see that the wires coming off the
                > > > transformer to the filter caps were melted where they touched the
                > > > transformer (it was quite hot).
                > > >
                > > > After doing some investigation, I found two things wrong with the
                > > > circuitry. First, a number of the capacitors were cracked (not
                > the
                > > > electrolytics), some of them so badly as to lose parts of their
                > > > coatings. Also, some of the transistors "legs" were touching
                > each-
                > > > other. I suspect that the sounds I heard were the capacitors
                > > > cracking. The electrolytics all seem to be fine, but most of the
                > > > dipped ones with color bands on them seem to be bad, and many of
                > the
                > > > solid brown ones (ceramic?) look to be bad as well.
                > > >
                > > > That leaves me with a few questions. Are these "solid"
                > capacitors
                > > > prone to cracking, and can they be replaced with modern
                > equivalents?
                > > > How do I read these color stripes for values, ratings, etc.?
                > Most of
                > > > the sources I've looked at don't say which direction you read
                > from
                > > > (the top end or the wired end), nor do they say what color they
                > are
                > > > underneath it all (most of them seem to have sort of mustard-
                > colored
                > > > bottoms).
                > > >
                > > > And, if the transistors wires were touching when it was turned
                > on, is
                > > > it likely that the transistors have been terminally damaged and
                > need
                > > > replacement? It's worth it to me to repair this organ, as it's
                > quite
                > > > rare and I've been looking for one for a long time.
                > > >
                > > > Thanks in advance for any advice.
                > > >
                > > > -- Robert
              • Dave Mucha
                A few words of advise if you didn t start on the clean up. Take digital photos of everything you can. Espically close ups of the caps and any other component
                Message 7 of 10 , Jan 1, 2004
                  A few words of advise if you didn't start on the clean up.

                  Take digital photos of everything you can.

                  Espically close ups of the caps and any other component part
                  numbers. You will not get that data again if it flakes and you touch
                  it.


                  Also, cap-juice is corrosive. You MUST clean it. Look at any angles
                  it might have squirted and clean it. Us a toothbrush to get under
                  resistors and such whereever you can.

                  And my last word of adcvise is that the organ music from Phantom of
                  the Opera will delight crowds. Since I don't play, it has always
                  delighted me.

                  Dave









                  --- In Electronics_101@yahoogroups.com, MUSIBIKE@j... wrote:
                  > I was an organ repair person at a music store here in Houston. Seen
                  a
                  > good many like this one.
                  >
                  > That one was most likely made in the late to mid 60's? I have an old
                  > Thomas organ that the store gave me. The wife loves it.
                  >
                  > Verify that the LESLIE is not constantly spinning. There might be
                  some
                  > loose junk like dead roaches and maybe even a mouse skeleton
                  rattling
                  > around in there. The fist thing is to UNPLUG it and clean out the
                  obvious.
                  >
                  > Pull out the power supply amplifer subassembly and check all of the
                  > old electrolytics and see if there is anything coming out of the
                  > transformer like tar. Sometimes those get a shortwed turn in them
                  and
                  > there is no salvatuion for them. You have to rig something else.
                  But,
                  > that is all doable.
                  >
                  > Every city has music stores where Church organs are sold and
                  > supported. Get yourself a manual on the unit if you are not too
                  > familar with them.
                  >
                  > A lot of those older transistors will survive what you have sated
                  > above because those older circuits limit the short circuit currents
                  > going to them. But, in the power amp or REVERB section maybe not.
                  >
                  > I would get a variac and bring the organ to a reduced input power
                  > voltage of about half to start with. The capacitors must rejuvinate
                  > their electrolytes if they have not been used for a good while.
                  Watch
                  > to see that things don't smoke out though. Take a voltmeter and see
                  > what happens across caps over a few minutes to see if these recover.
                  > You will have to replace the cracked ones for sure.
                  >
                  > I can post a capacitor color code in the photos section.
                  >
                  > MUSIBIKE
                  >
                  > --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...>
                  wrote:
                  > > I just bought an old transistorized combo organ. When I plugged
                  it
                  > > in and turned it on, I heard a number of small "tinkling"
                  > > and "ticking" sounds from inside the case. Dispite this, the
                  organ
                  > > played reasonably well, although it was quite out of tune
                  > > and "scratchy" sounding. After being turned on for about 15
                  minutes,
                  > > white smoke and a burning plastic smell started coming out of the
                  > > case. I switched it off and eventually the smoke dissapated.
                  After
                  > > taking the case off, I could see that the wires coming off the
                  > > transformer to the filter caps were melted where they touched the
                  > > transformer (it was quite hot).
                  > >
                  > > After doing some investigation, I found two things wrong with the
                  > > circuitry. First, a number of the capacitors were cracked (not
                  the
                  > > electrolytics), some of them so badly as to lose parts of their
                  > > coatings. Also, some of the transistors "legs" were touching
                  each-
                  > > other. I suspect that the sounds I heard were the capacitors
                  > > cracking. The electrolytics all seem to be fine, but most of the
                  > > dipped ones with color bands on them seem to be bad, and many of
                  the
                  > > solid brown ones (ceramic?) look to be bad as well.
                  > >
                  > > That leaves me with a few questions. Are these "solid"
                  capacitors
                  > > prone to cracking, and can they be replaced with modern
                  equivalents?
                  > > How do I read these color stripes for values, ratings, etc.?
                  Most of
                  > > the sources I've looked at don't say which direction you read
                  from
                  > > (the top end or the wired end), nor do they say what color they
                  are
                  > > underneath it all (most of them seem to have sort of mustard-
                  colored
                  > > bottoms).
                  > >
                  > > And, if the transistors wires were touching when it was turned
                  on, is
                  > > it likely that the transistors have been terminally damaged and
                  need
                  > > replacement? It's worth it to me to repair this organ, as it's
                  quite
                  > > rare and I've been looking for one for a long time.
                  > >
                  > > Thanks in advance for any advice.
                  > >
                  > > -- Robert
                • MUSIBIKE@juno.com
                  The two capacitor manufacturers I currently use in my production are, 1.) Illinois Capacitor, (847)675-1760, www.illcap.com 2.) United Chemi-Con,
                  Message 8 of 10 , Jan 2, 2004
                    The two capacitor manufacturers I currently use in my production are,
                    1.) Illinois Capacitor, (847)675-1760, www.illcap.com
                    2.) United Chemi-Con, (847)696-2000, www.chemi-con.com

                    I think you should chose replacements out of the Metallized
                    Polypropylene group for best physical mounting and performance.

                    Post a fax number and I will FAX you a copy of my old capacitor color
                    code sheets.

                    And, there are others but, I have had the best luck with these two.

                    MUSIBIKE

                    --- In Electronics_101@yahoogroups.com, MUSIBIKE@j... wrote:
                    > I have several capacitor catalogs at work. Will be there tomorrow. I
                    > can get you the phone numbers and LINKs for them. They will provide
                    > you FREE catalogs and help. They want to sell you CAPACITORS. The same
                    > is true for any semiconductor like older transistors. I have worked on
                    > a couple of those old things. All ANALOG. No sampling, simple.
                    >
                    > I think the new KEYBOARDS are way over teched these days. Not fixable
                    > without a programmer and specialized soldering tools.
                    >
                    > All you need to fix that one you have there is common sense and a
                    > 30watt iron.
                    >
                    > Send you the Capacitor info tomorrow at work.
                    >
                    > MUSIBIKE
                    >
                    > --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...> wrote:
                    > > Hi "Musibike" --
                    > >
                    > > Thanks very much for the advice. The organ was made sometime in the
                    > > late-'60s to early-'70s, by an Italian company. This one doesn't
                    > > have a Leslie, so at least we can rule that out. All of the
                    > > electrolytics look clean and not deformed to me. I should've brought
                    > > it up on a variac, but I was too excited and impatient, and I
                    > > suspected that it had been damaged in shipping (you wouldn't BELIEVE
                    > > how poorly packed it was, and the case was cracked during transit),
                    > > so I just spaced on that. I'll pull the transformer and check it
                    > > out.
                    > >
                    > > Since the ceramic (?) caps that are cracked are mounted on PCBs, I
                    > > presume that I need to remove the PCBs to get to the back sides, so I
                    > > can melt the solder to get them out. Am I correct in assuming that I
                    > > don't need to use heatsinks when soldering on a PCB, just a low-
                    > > wattage soldering pencil?
                    > >
                    > > Also, I've seen some color codes for caps and am trying to memorize
                    > > them, but the two things that I have never seen explained is which
                    > > end you read from--the end with the wires or the top end, and what
                    > > the base color of them is. Some of these caps look to be entirely
                    > > covered with color stripes, but on some, it looks like the cap itself
                    > > is a sort of mustard color, although that may be another color.
                    > >
                    > > I think I'm dealing with two different kinds of caps here, and I want
                    > > to make sure I'm describing them correctly. The kind that have
                    > > stripes are irregular rectangles with rounded corners. They look
                    > > like they were formed by dipping into some material. The surface is
                    > > quite smooth and shiny. The other kind I described have numbers
                    > > printed on them. They are a solid brown color, more like irregular
                    > > cylinders and have a matte finish--rather like terra-cotta. If I
                    > > knew what to properly call these, it would help.
                    > >
                    > > Thanks again --
                    > >
                    > > Robert
                    > >
                    > >
                    > >
                    > >
                    > > --- In Electronics_101@yahoogroups.com, MUSIBIKE@j... wrote:
                    > > > I was an organ repair person at a music store here in Houston. Seen
                    > > a
                    > > > good many like this one.
                    > > >
                    > > > That one was most likely made in the late to mid 60's? I have an old
                    > > > Thomas organ that the store gave me. The wife loves it.
                    > > >
                    > > > Verify that the LESLIE is not constantly spinning. There might be
                    > > some
                    > > > loose junk like dead roaches and maybe even a mouse skeleton
                    > > rattling
                    > > > around in there. The fist thing is to UNPLUG it and clean out the
                    > > obvious.
                    > > >
                    > > > Pull out the power supply amplifer subassembly and check all of the
                    > > > old electrolytics and see if there is anything coming out of the
                    > > > transformer like tar. Sometimes those get a shortwed turn in them
                    > > and
                    > > > there is no salvatuion for them. You have to rig something else.
                    > > But,
                    > > > that is all doable.
                    > > >
                    > > > Every city has music stores where Church organs are sold and
                    > > > supported. Get yourself a manual on the unit if you are not too
                    > > > familar with them.
                    > > >
                    > > > A lot of those older transistors will survive what you have sated
                    > > > above because those older circuits limit the short circuit currents
                    > > > going to them. But, in the power amp or REVERB section maybe not.
                    > > >
                    > > > I would get a variac and bring the organ to a reduced input power
                    > > > voltage of about half to start with. The capacitors must rejuvinate
                    > > > their electrolytes if they have not been used for a good while.
                    > > Watch
                    > > > to see that things don't smoke out though. Take a voltmeter and see
                    > > > what happens across caps over a few minutes to see if these recover.
                    > > > You will have to replace the cracked ones for sure.
                    > > >
                    > > > I can post a capacitor color code in the photos section.
                    > > >
                    > > > MUSIBIKE
                    > > >
                    > > > --- In Electronics_101@yahoogroups.com, "Robert" <rch427@y...>
                    > > wrote:
                    > > > > I just bought an old transistorized combo organ. When I plugged
                    > > it
                    > > > > in and turned it on, I heard a number of small "tinkling"
                    > > > > and "ticking" sounds from inside the case. Dispite this, the
                    > > organ
                    > > > > played reasonably well, although it was quite out of tune
                    > > > > and "scratchy" sounding. After being turned on for about 15
                    > > minutes,
                    > > > > white smoke and a burning plastic smell started coming out of the
                    > > > > case. I switched it off and eventually the smoke dissapated.
                    > > After
                    > > > > taking the case off, I could see that the wires coming off the
                    > > > > transformer to the filter caps were melted where they touched the
                    > > > > transformer (it was quite hot).
                    > > > >
                    > > > > After doing some investigation, I found two things wrong with the
                    > > > > circuitry. First, a number of the capacitors were cracked (not
                    > > the
                    > > > > electrolytics), some of them so badly as to lose parts of their
                    > > > > coatings. Also, some of the transistors "legs" were touching
                    > > each-
                    > > > > other. I suspect that the sounds I heard were the capacitors
                    > > > > cracking. The electrolytics all seem to be fine, but most of the
                    > > > > dipped ones with color bands on them seem to be bad, and many of
                    > > the
                    > > > > solid brown ones (ceramic?) look to be bad as well.
                    > > > >
                    > > > > That leaves me with a few questions. Are these "solid"
                    > > capacitors
                    > > > > prone to cracking, and can they be replaced with modern
                    > > equivalents?
                    > > > > How do I read these color stripes for values, ratings, etc.?
                    > > Most of
                    > > > > the sources I've looked at don't say which direction you read
                    > > from
                    > > > > (the top end or the wired end), nor do they say what color they
                    > > are
                    > > > > underneath it all (most of them seem to have sort of mustard-
                    > > colored
                    > > > > bottoms).
                    > > > >
                    > > > > And, if the transistors wires were touching when it was turned
                    > > on, is
                    > > > > it likely that the transistors have been terminally damaged and
                    > > need
                    > > > > replacement? It's worth it to me to repair this organ, as it's
                    > > quite
                    > > > > rare and I've been looking for one for a long time.
                    > > > >
                    > > > > Thanks in advance for any advice.
                    > > > >
                    > > > > -- Robert
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