EDC SR-99 Project – Introduction

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/

Dubsounds: http://dubsounds.proboards.com/thread/3093/edc-schematics-service-manual-needed

Electro-Music:  http://electro-music.com/forum/viewtopic.php?p=432562#432562

Vintage Synth Explorer: http://forum.vintagesynth.com/viewtopic.php?f=1&t=104505



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