Help solve my Deluxe Memory Man wierdness?

[Scruffie]

Okay,

Here ya go.

U2
p1 -6.1V
p2 -3.1V
p3 -3.1V
p4 -14.9V
p5 -6.7V
p6 -6.7V
p7 -6.7V
p8 0V

Pin 1 is 6.1V? Double check that because you might have a bad opamp there.

Edit: Scratch that... that's the weirdly biased opamp.

[honkyjonk]

Okay,

So I soldered the probe directly to pin 1 of U1 just to make absolutely sure I wasn't just continually in error when placing the probe on there. Still there is no signal. BUT, I did notice that I get a very faint signal at this spot when the DMM is not powered on. There is also a very brief strong signal when the power switch is cycled. (almost between off and on, it pokes through very briefly)

Does C1 need to be replaced anyway, if I can get signal right before it, but not after it? I also have the part to replace C3 (the 47uF)

[garcho]

There is also a very brief strong signal when the power switch is cycled.

bad caps in the power supply can do that

[honkyjonk]

Okay,

Well, it seems to be fixed for the moment. I'm still not getting signal at pin 1 of U1 fwiw. Hmmmm.

But since I had the caps, I replaced C3, C18 and the power supply caps. The one thing I noticed when doing this was that C37, the 100uF cap in the power supply had a loose leg, and was probably not making contact. I'm betting that was it, but I don't know. Does that sound like something that would cause my symptoms?

Don't know why even after this I still am not getting signal from U1 output, but I just decided to try plugging into the echo out, and there was that strong echo I love, with the insane feedback knob working again. Hmmmm. We'll see if it lasts. . . . I hope so!

Thanks Scruffie and Garcho for the help!

[honkyjonk]

Oops,

Spoke too soon. I put it back together and I was back to my same original problem. I realized something must have grounding out or something glitchy was happening. I found out that when I touched the 4.7uF cap beside the feedback pot (C8 I think?), the feedback came roaring back.

It seems that the pot had pushed over that cap and broken it's connection with the board. Jeez.

Okay, but it's back together now and working great. Yay.

[Scruffie]

Nicely done, glad you got her going again, C8 is part of the compander circuitry so that'd explain it.

No idea why the probe wasn't working for you!