My MM4 was working perfectly but all of a sudden started making quite a lot of hiss/static/white noise once activated (or when in alternate bypass). Have done the usual reset etc but that didn't help.
Everything looks fine inside - the MM4 chip is well seated, and I am using the Line 6 power supply, so shouldn't be the result of bad power.
One interesting thing to note is that if I plug a cable into the Right output the noise on the left stops and transfers over to the right channel.
All I can gather is that something on the right side of the stereo signal is faulty as the left side is totally fine when not summed to mono with the right. And/or when the guitar signal is split into stereo before processing the signal is being compromised on that side.
Where would I look to troubleshoot this? I am comfortable with a soldering iron and a can of contact cleaner if it is down this road.
I am in Australia so the choices of Line 6 repairers is not great..
Although it is working OK for now, I don't want it to fail on me at a bad time, so would rather have it sorted..