Light metal effect doesn't work

[Leka]

Hello!

I just found my old guitar pedal project called Light Metal Effect which has never worked right. Now I'm finally trying to get this thing done.

It should be a ring modulator which is adjustable and it should follow the guitar notes like an octaver. (Yes I know it's grazy... )
The problem is that it doesn't follow the notes of guitar, the ring modulation tone just sticks at the same where it is set. Another visible problem is that the led in it doesn't light at all.

I hope that someone could help me because my analog signal knowledge isn't that great and this thing looks quite complicated with 11 IC's in it...
Here is a link to the plans for the project with complete schematics and descriptions:
http://www.elisanet.fi/~d635260/lme/

I have double checked all the components and pcb many times.

Please tell me which part should I start to investigate, I have oscilloscope / signal generator and I know how to use them.

It would be great to finally finish this project as it is now twenty years ago when I started it as my first guitar effect project...

_Any_ comments highly appreciated!

- Leka

[Mark Hammer]

I've never built it, but I know the Penfold project, as it forms the basis of the mono guitar-to-synth interface Robert Penfold had in Practical Electronics (which I scanned and posted here: http://hammer.ampage.org/files/GuitarP2V.PDF ; incidentally the link you provided does not work anymore).

Certainly one possibility is that one or more of the various CMOS chips in it has fried, but you note that the components seem fine. Have you checked the supply voltages on the various chips to make sure that power is reaching everything as it should?

[Leka]

Thank you Mark for the other project's info!

I updated the above link to my project.
There are many similarities with these two projects!

Yes, the cmos chips are sensitive, I have to check that the cmos chips are ok. (IC4 & IC11) I guess if IC11 is fried, the led doesn't light as it is now...
I have checked that all the chips are getting + and - ok.

Did you build that crazy analog synth guitar interface?

[Mark Hammer]

Actually, I've built two of them, but I still haven't wired/powered either one up yet. I'm planning it for this summer. Too many other things to do first.