Thought I'd share this experience in case someone else has the same problem - it might save you some hassle/cash.
A while back my MXR M87 died. The level meter was still functioning but there was absolutely no sound coming from the pedal output. I did all the usual quick fixes (contact cleaner on jacks, replaced footswitch etc) but to no avail.
After a bit of digging I discovered that the output op-amp in this pedal (TLC2262 in case you were wondering) has a maximum voltage of 16V. Obviously this would normally be OK in a pedal that runs at 9V, except that MXRs "Constant Headroom Technology" feature is essentially a charge pump circuit that doubles the pedal's internal voltage to 18V. It shouldn't take a genius to work out what therefore ensues if, like me, you're unlucky.
I replaced the TLC2262 with an AD822 (which has a supply voltage of 18V) and my pedal now lives and breathes again. I believe MXR will fix pedals under warranty for a flat fee of £75, whereas replacing the blown chip cost me less than a tenner and a few minutes fiddling with a soldering iron (the TLC2262 and AD822 chips are both surface mount - soldering these can be tricky unless you're experienced in doing so).
It appears that mine is not an isolated issue as a quick Google uncovers many such failures, so I figured I'd pass this info on in case any other BC members' M87s suffer the same fate. Please use or disregard this information as you see fit!
Hello! I recently did that. Replaced with AD822ARZ. But this not solved the problem. Now pedal has sound but compression indicatos still lit. All compression indicators glow but after about 5 minutes indicators starts to dim one by one. At that time the more release time I set the less indicators are glow and vice versa. Attack and ratio controls work predictably. Dont know what to do.
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MXR M87 Bass Compressor Repair - May Be Of Use To Someone?
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Hello! I recently did that. Replaced with AD822ARZ. But this not solved the problem. Now pedal has sound but compression indicatos still lit. All compression indicators glow but after about 5 minutes indicators starts to dim one by one. At that time the more release time I set the less indicators are glow and vice versa. Attack and ratio controls work predictably. Dont know what to do.