Way too much low end
and maybe the dying (depends how it dies)
point my brain towards the preamp
Methinks maybe the low end is caused by a failed short-circuited cap. (because, IMO caps fail more often than resistors)
so maybe check C1 and C2.
after that go through the gain structure and see if you can find a point where the gain is WAY off for the bass.
Since you hear blocking distortion on the distortion channel, the filtering that removes the bass is before the clipping diodes. And because they are marked as polarized, they might be electrolytics, so check C18 and C22
Also it would be easy to check the switching voltages with a multimeter.
This is unfortunately only a guess at a diagnosis for the farty sound, not the dying.
more information about the momentus mortis would be nice. Does it still light up? Have you probed parts of the preamp to see where the signal stops ? Is the switching FETs getting the correct DC voltage?
and maybe the dying (depends how it dies)
point my brain towards the preamp
Methinks maybe the low end is caused by a failed short-circuited cap. (because, IMO caps fail more often than resistors)
so maybe check C1 and C2.
after that go through the gain structure and see if you can find a point where the gain is WAY off for the bass.
Since you hear blocking distortion on the distortion channel, the filtering that removes the bass is before the clipping diodes. And because they are marked as polarized, they might be electrolytics, so check C18 and C22
Also it would be easy to check the switching voltages with a multimeter.
This is unfortunately only a guess at a diagnosis for the farty sound, not the dying.
more information about the momentus mortis would be nice. Does it still light up? Have you probed parts of the preamp to see where the signal stops ? Is the switching FETs getting the correct DC voltage?