Shin-ei Mute Box not working, I do hate repairs !

[tomtom]

Yes, I have repaired/fixed some vintage nonworking FX, mainly old ones like EH stuff (a pain, really) and I do not like finding the wrong thing at all !

I have bought this one for cheap and it's something like an old Mutron with quite a strange optocoupler.
The first opamp works, as I do have a sound when bypassed (not true bypass) but something seems wrong once engaged. Only the band-pass setting works (I mean I have a sound, like a distorded one).

I do have to check somewhat everything but I felt I need to post something here, maybe you have tips for troubleshooting !

Thanks for any help.
Tom

[Dan N]

I have never seen nor heard of a Shin-Ei Mute Box. Is it like the Univox EffectMatic?

http://www.univox.org/effects/effectmatic.html

[tomtom]

Yes, it has the same controls, it seems to be another rebranded Mutron in a Maestro style box.