Alesis MicroVerb - passing signal but no effect

[Tone Meister]

OK, this is probably a bit above my pay grade, but I want to give it a shot anyway. I have an Alesis MicroVerb from October 1986 that is passing signal but does not produce an effect, and the input volume pot has no effect on the signal path.

When injecting a 1K tone into either input, I can trace the signal up to the U13 flip flop, but am unable to pick up the signal at the input of the Input Volume Pot. Thus the input volume pot has no effect on the signal path. The Output Volume Pot does increase and decrease volume, with or without DC power connected to the unit. I don't have the experience to suss this out, nor do I have a logic tester, so I figured I'd run it by you folks here to see if this is a problem any of you have experienced before.

More pictures are available HERE but below is a shot of the part of the circuit I suspect:

[Jazz P Bass]

What is happening at Pin #1 of the flip-flop IC, the output enable pin?
It should go high.
Datasheet: http://www.tautec-electronics.de/Dat.../CD74HC374.pdf

[S2udio]

Take it all supply voltages are present ?
Clock signal there ?

[Tone Meister]

Take it all supply voltages are present ?
Clock signal there ?

Let me preface my reply with this: I am little more than a clueless hack. I understand some of the very basics, but I'm really unprepared to suss out problems with digital logic. For the time being, I've put this unit aside to take on a couple of "friendlier" projects that make me appear much more like a "real" tech.

I can't say that all supply voltages are there, but the power supply does work; however, I have not traced power through the unit as of yet. I injected the signal as described in my initial post and could not trace it further than the flip flop. I never got around to responding to Jazz P Bass's suggestion for the reasons mentioned above.

I would like to get this ole POS working again because it's just so darn convenient for those times when I need to go minimalist. I'll be glad to follow any troubleshooting techniques you can offer, and thanks for your reply.