Soviet multi-fx help!

[6x2]

Slightly off-topic, but does anybody know good web resources about Soviet effects? I've googled out some stuff that's mostly in Russian or then totally obscure...

Thing is, I was given a Soviet-era (probably studio) effects processor - "Zvukoprozessor Vestnik 3VP-081 Stereo" that powers up and gets an input but doesn't pass sound through. It self-oscillates in a crazy fashion - it's got some modulation thing going on that seems to be the source of that + it makes other weird sounds, but nothing related to the input signal... Pretty useless as it is, I'd like to see if I can fix it.

I've figured out it's a reverb/echo unit with delay and modulation, but I can't  quite figure the circuit board out. Loads of ICs and strange looking caps with cyrillic writing. Most of the resistors are brown and the value is indicated in writing. Input and output jacks are glorious DIN... After a quick inspection, I didn't find any clearly burnt components.

I expect EXTREME low fidelity from the unit. Might be fun.

Any hints where to start from?

Thanks,

6x2