Troubleshooting Music Lights (ML1)

[sacktap]

Assembled my ML1 kit years ago; it's been packed away and I decided to take it out. Unfortunately, it doesn't work; no light at all.

I've double/triple-checked the solder joints.
Transformer: primary coil measures ~0.8 Ohm, and secondary coil ~20 Ohm.

The primary coil is fed from the audio input.

I removed the Mid and Low pots in an attempt to isolate the problem.

If I short the SCR, Anode--Cathode, or Anode--Gate, the light turns on.

Any ideas on where to start? Which piece is most likely to fail?


Related question: By tapping around randomly with one probe, I can trigger quick flashes of the lightbulb. Is this an effect of capacitive coupling?

[sacktap]

Still want to fix this

[RDEngineer]

Call our tech support, 585-924-4560. I assume it use to work. Because yousay it is "yesrs" old make sure you tell the tech this is an older unit sionce the design has changed. It is next to impossible to trouobleshoot problems via email or the forum and we don't always see forum posts on a regular basis.

[gfg123GFG]

Thanks for your post. I am new here...

Regards
FUAD