Do you know what model number the
triac was or the specs of the
triac so i can find an alternative part if need be, would a burnt out pot on the controller be the issue of
channel 1-3 being
nfg? And the masters acting strange ? Do you happen to know the part used for the
connector on the pack side
socket mount?
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Fixing these things is a breeze if you have an oscilloscope, and really difficult without one. The general rule for these things, once they were finished at the factory, was that if they didn't work there was usually only one or at most two things wrong. To fix them, you had to figure out what was actually wrong with it first - just swapping parts was a waste of time and material. A bad solder joint could waste an entire afternoon if you weren't careful.
The
triac was a custom packaged Unitrode 30A 400V device on a TO-3
base with a
ceramic isolator and a soft plastic
cover. Triggering was an
opto-isolator. Unitrode was bought and shut down by Texas Instruments years ago, so new parts are not available. If I had to replace one, I'd see if I could make a Littelfuse Q6035P Series 35 A 600 V
TRIAC TO-3 work. Ratings look right and the package has the right outline. Only problem is that the Unitrode device had three vertical copper pins soldered straight into the mainboard while the Littelfuse has three push-on connectors. If I were working on it, though, I'd make sure you've got proper signal and ramp voltages on the control board before I started unmounting the mainboard. To remove the board, there are a row of screws in the bottom that are the
triac mounting screws, and then a few more that are the standoffs. Take them all out and the board comes out. When you put it back, clean up the
heat sink compound and put a small dab (1/8" or so) in the middle of each
triac base. When you do up the screws it spreads out evenly and works properly. That was the factory assembly process.
If the master pots were both open, it would do that, but why would both be open? I'd check all the voltages on the controller board - it's dead simple inside - and see what's going on. If I remember correctly, the cross
fader was done with a time-domain multiplexer - each set of slider levels was sent to an output filter for times determined by the settings of the masters. That way a scene A pot fading to a scene B pot at the same
level didn't dip half-way through the
fade. Again, if anything goes wrong with the ramps or the pots, it creates a weird-looking result that's actually fairly easy to fix once you figure what's broken.
If you're asking for the control cable connectors, they're a low-cost (but decent quality)
Cannon connector. 10 pins. I'll see if I can find a part number somewhere, but I expect they've been out of production for decades. This product was a new
release in 1981, so it's been a while.