This may or may not be the SR-99 I replaced the battery clip on in an earlier project.
There’s a video associated with that: https://www.synteknik.com/samples/edc-sr99.3gp
Anyway, although it appears to work, there’s no sound (there’s none on the video either..).
I’ve had it in bits, and although I can see a replaced 4011 sitting in a socket (not usual), I can’t get any sound out of it. It appears to program OK, though..
The SR-99 uses a TC5514P chip instead of the DR-55’s TC5501P, but it’s the same principle, so I checked the output pins when the sequence is running, and all four pins are high and stay high. That’s wrong, as they should only go high when there’s a sound. So it’s probably a bad memory chip.
I have two on order from vintage planet as I write this…
Related forum links:
Music Electronics Forum: http://music-electronics-forum.com/t45826/
Vintage Synth Explorer: http://forum.vintagesynth.com/viewtopic.php?f=1&t=104505