Dead Astronaut Skyscape Chorus - No Wet Signal

[Strat68]

Got back to this after a couple months. There is no wet signal coming through. All ICs have voltage. Part of my problem is not knowing exactly how this circuit works. I traced an audio signal to the cathode of D3 then no signal into R12 which feeds directly to the input of the MN3007. I've reflowed solder and was going to re-verify the parts again. The Level pot works as intended but no others.On the MIx pot I have signals on lugs 1 and 2, nothing on 3. On the trimmer there is signal on lug 2.
I've switched out both the MN3007 and the CD4047 with no change.

Any hints on where to look will be much appreciated.

 

[jwin615]

Did you sub transistors or possibly mix up the the npn and pnp?
Q3 socket soldering cold/poor contact? Looks tilted.

 

[Strat68]

Did you sub transistors or possibly mix up the the npn and pnp?
Q3 socket soldering cold/poor contact? Looks tilted.

I'll check. Thanks

 

[Strat68]

It looks like both transistors are NPN and correctly oriented. I am wondering about the CD4047.

 

[dcfvgb]

Late to the party...

IC4 is a low frequency oscillator (LFO) that creates a small low frequency ac waveform that feeds the 4047, then the 4047 turns the ac waveform into a squarewave that is used as the clock or timing signal to run the bbd chip. (If you don't know how a bbd works electrosmash has a good artcle on them using an mn3007)
If the lfo isnt working the bbd wont work.

Use you DMM set on ac volts on pin 1 of ic 4 to see if there is a small ac voltage going up and down. Adjusting rate pot will speed it up and slow it down. If it's a steady voltage, the LFO probably isn't working.

If the LFO is working, pin 10 and 11 of the 4047 should do something similiar.

At least then you will know if the timing circuit is working. I usually use a scope to debug timing circuits, much easier.

Your rate pot wiring from this angle looks supicious.

 

[Strat68]

Late to the party...

IC4 is a low frequency oscillator (LFO) that creates a small low frequency ac waveform that feeds the 4047, then the 4047 turns the ac waveform into a squarewave that is used as the clock or timing signal to run the bbd chip. (If you don't know how a bbd works electrosmash has a good artcle on them using an mn3007)
If the lfo isnt working the bbd wont work.

Use you DMM set on ac volts on pin 1 of ic 4 to see if there is a small ac voltage going up and down. Adjusting rate pot will speed it up and slow it down. If it's a steady voltage, the LFO probably isn't working.

If the LFO is working, pin 10 and 11 of the 4047 should do something similiar.

At least then you will know if the timing circuit is working. I usually use a scope to debug timing circuits, much easier.

Your rate pot wiring from this angle looks supicious.

Thank you very much. I had give up on it but it’s still on my bench. I wish I hadn’t dropped out of electrical engineering. I have a handheld scope to finally use.

 

[Strat68]

And, yes, I noticed the pot wiring a few days ago and cleaned it up.