Super quiet Boss MT-2 Metal Zone.. ugh

[effectsbay]

So.. I've been having fun problem solving/fixing various pedals. Because of this, my friends know this, I often get some donated pedals to work on. Well, I just received the Boss Metal Zone to work on. Not my favorite pedal, but regardless, working on it is a challenge.

So when it was given to me, they said it was dead when engaged, but sound comes through when it's 'off'. So after checking, that person was sort of right. When 'on' the light turns on, but you *can* hear the effect, it's just really, really, really quiet. All the controls work - level, distortion, tone/EQ controls, but the output is just insanely quiet.

I cracked it open to see if anything was damaged. All solder points look good. I inspected the caps, and those appear good. Nothing obvious.

Pulling out the audio probe, I started poking around to see when/where things get quiet.

In this diagram..
http://milas.spb.ru/~kmg/files/schematics/boss/mt2/mt2_05.jpg
http://milas.spb.ru/~kmg/files/schematics/boss/mt2/mt2_06_shema.jpg

Things appear to get quiet in the bottom right of the PCB.

Like I mentioned, the effect appears to be working well.. just quiet. I would initially suspect one of the ICs, but because it's sounding okay, I'm thinking it might be some other component having a problem. Unless we're dealing with a faulty opamp

I wanted to post this here, in case someone knows exactly what is happening, before I start replacing ICs.. or have a possible different direction for me to look at.

Thanks everyone!
hank

[anchovie]

Probe the two outer pins of Q2 with the effect engaged - that's the switching FET that should be letting the signal through when on. If the side nearest the edge of the board is loud and the other is quiet then that's the culprit. If both sides are quiet, you'll need to work backwards through the schematic to find the point at which it becomes loud.

[animal]

So.. I've been having fun problem solving/fixing various pedals. Because of this, my friends know this, I often get some donated pedals to work on. Well, I just received the Boss Metal Zone to work on. Not my favorite pedal, but regardless, working on it is a challenge.

So when it was given to me, they said it was dead when engaged, but sound comes through when it's 'off'. So after checking, that person was sort of right. When 'on' the light turns on, but you *can* hear the effect, it's just really, really, really quiet. All the controls work - level, distortion, tone/EQ controls, but the output is just insanely quiet.

I cracked it open to see if anything was damaged. All solder points look good. I inspected the caps, and those appear good. Nothing obvious.

Pulling out the audio probe, I started poking around to see when/where things get quiet.

In this diagram..
http://milas.spb.ru/~kmg/files/schematics/boss/mt2/mt2_05.jpg
http://milas.spb.ru/~kmg/files/schematics/boss/mt2/mt2_06_shema.jpg

Things appear to get quiet in the bottom right of the PCB.

Like I mentioned, the effect appears to be working well.. just quiet. I would initially suspect one of the ICs, but because it's sounding okay, I'm thinking it might be some other component having a problem. Unless we're dealing with a faulty opamp

I wanted to post this here, in case someone knows exactly what is happening, before I start replacing ICs.. or have a possible different direction for me to look at.

Thanks everyone!
hank

Dude, could you fix the problem??
i have the EXACTLY same problem here !! HELP !!! jejejej