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T Series 'PEDAL SUSTAIN' problem...

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    T Series 'PEDAL SUSTAIN' problem...

    On my T 500 the pedals are always in sustain mode, and I want them not to sustain the note. I looked under the "pedal sustain" switch and I see that when the switch is not depressed..so not in what would be the position to sustain the note...there is a contact that is closed. I thought maybe the contact points are dirty, so I bridged the two pieces of metal with a screw driver. The note still sustains.

    I will never want a pedal note to sustain, so is there a way to by pass or wire the switch permanently to stop the sustain effect but still have use of the pedals ?

    #2
    It's SO long since I sorted this one out on my own rig... not sure that I can recall exactly what does this, but I'm fairly sure the answer is still under those tabs. I'll see if I've got any notes on the subject. It was either grounding or NOT grounding something, possibly via a capacitor.
    I'll be back soon.
    -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
    -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
    -DIY 760 FrankenLeslie/rat hideout-
    -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
    -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

    Comment


      #3
      In my notes I'd only mentioned:
      "Pedals started sustaining. Wire under tabs had broken off. Fixed it."
      But no mention of which wire nor a picture.
      Also in there was:
      "Pedal sustain is on accomp board's pin 12."
      "Also on the older boards pedal legato and sustain are activated via pin3 on the pedal divider board. Pin3 is instead a ground pin on the T500 pedal divider board."
      and there were some notes from when I removed the tabs altogether:
      "Found R403 (4.7k) which is under the pedal tabs. (joins Terminal pins 2and4) and ran a 3.3k in parallel to get a SLIGHTLY drier decay.
      Added a 220nF (polyester code 224) between terminal pins 1and4 to get a smoother sine tone in the pedal: less raspy.
      Removed wires which ran from pedal tabs to accomp board, hard wired sustain to off, mute to off
      + and 16’ to on."


      -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
      -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
      -DIY 760 FrankenLeslie/rat hideout-
      -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
      -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

      Comment


        #4
        This post probably doesn't add anything, but it's worth looking at:
        https://organforum.com/forums/forum/...361#post499361
        It's specifically about the mods I had to make to bypass the auto-accomp board, where the sustain and 16/8 switching are produced.
        -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
        -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
        -DIY 760 FrankenLeslie/rat hideout-
        -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
        -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

        Comment


        • Two Finger Tony
          Two Finger Tony commented
          Editing a comment
          Well, I too would like to hard wire the sustain in the 'off' mode. I thought that when I got under that left cheek block that contains the Leslie and pedal rocker switches that I would see the back sides of individual rocker switches with 2, 3, or 4 spade or solder connections as in car or boat applications of rocker switches.

          LOL,I found out they only look like rocker switches...they are all on one board, and the pedal sustain switch has a resistor and a capacitor wired to it and maybe more stuff. I thought that bridging the two pieces of metal that the switch separates to create sustain would solve a dirty contact problem and if that worked I would have soldered a wire for a permanent fix.

          So is it posible that the switch is not being energized and that that sustain is the default result of the open circuit that mimics the contacts in the open position ? Are those rockers operating on DC or AC ? The wires and the contact strip are very light weight, so there cant be much load I am thinking. I have a multi-meter...if you can tell me what to set it on I can check to see if there is any juice going to the switch. And thanks for your replies !

        #5
        Hmm, my one didn't have a board, but separate contacts on each switch. Probably still follows the same gist though.
        From memory the tabs, if passing audio would have very low level AC, while anything else would be DC. eg: the leslie speed switch has 12VDC going to a relay.
        I'll see if I can find a description in the manual of the pedal sustain operation.
        If you don't have the manual I've put it up here:
        https://archive.org/details/T500Serv...PAGESREORDERED
        -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
        -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
        -DIY 760 FrankenLeslie/rat hideout-
        -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
        -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

        Comment


          #6
          Here's the best I could find on the tab itself:
          Click image for larger version  Name:	T500 pedal sustain_001.jpg Views:	0 Size:	266.4 KB ID:	717762
          The answer has got to be one of only a few variations.
          Run a wire from ground and try it at several points around the tab and R403/R402 and see if it does anything.
          Also see what pin 3 of the divider board does. It's involved, but see what happens if A) you detach it
          or B) if you ground it.

          As you can see it goes to pin 12 of the Autoaccomp, which adds a whole lot of extra fiddly circuits to the simpler design of the earlier models. At what is possibly the other end of that bit of the Accomp circuit is pin 19 which receives sustain voltage from pin 8 of the pedals. 12V I think.

          The cable loom between my pedals and organ chop have developed breaks, so before I can test any of these things myself I'll have to rewire the loom!
          -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
          -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
          -DIY 760 FrankenLeslie/rat hideout-
          -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
          -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

          Comment


            #7
            By the way, it's nice to get my head back into the puzzles of the T!
            I'd gotten completely out of the zone and my brain just wasn't making any sense of the electronic majickery inside it. I've been playing guitar and drawing cartoons, my own T had gotten to an electronic impasse. Maybe I'll get back to it after all.
            Thanks for that Tony!
            -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
            -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
            -DIY 760 FrankenLeslie/rat hideout-
            -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
            -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

            Comment


              #8
              Hello, I would like to start by thanking you for letting me join this forum! I too am having the same issue with the sustain on the foot pedals.

              I just acquired my T500 a few days ago - the mice had moved in... What was surprising, she still could fire up - but with a bad hum! At that point I had tested the foot pedals - they were not stuck on sustain. I did perform the first keyboard partner mod - Im curious if that might have caused the issue? I don't remember if I tested the pedals after I did the mod. I then proceeded to clean up and repair the damage from the mouse infestation. I had to pull the power / reverb amp board, and the percussion board.

              She's up and running. The second fuse down beside the percussion board was blown. I have it on leads to a 7.5 amp automotive fuse (didn't have a 6 amp around). That killed a fair amount of the hum - still a faint one. everything seems to be operational - except the sustain foot switch seems stuck on. I will add - after a while, the sustained note turns into static until I hit another foot pedal?

              Any help, or input would be appreciated!

              Comment


              • Papus
                Papus commented
                Editing a comment
                Welcome to the T club!
                With a little modification and patience, you'll have that T roaring and spitting like a console in no time.

                Safety notice: replace the motor run cap immediately!
                The old caps are liable to explode, sending toxic PCB oil and burnt paper everywhere

              #9
              Thank you Papus - I was planning on re capping the organ asap. Didn't even realize there was a capacitor right beside the motor.

              Comment


                #10
                d I still have not solved the pedal sustain problem...have you ?

                Comment

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