Alright... I've been busy with work this week, but just had some time to do some poking aroung this afternoon.
1. All 5 fusistors (2x680, 2x 390, 1x68) in the r-amp section test within 5% or so of marked value.
2. Same for the 3 large ceramic caps (2x0.47, 1x10). Well, I have a pretty cheap DMM, so the 0.47 ohm measured at 0.7 ohm. Still, no shorts or anything opened. I did test with everything soldered in, however.
3. I did not spot any cracked solder joints. Still, I reflowed most TRs in the r-amp section. No change.
4. I couldn't seem to find any info on the relay leads in the manual. The last pair of leads however show 0V before relay clicks, then a solid 25V.
So, unfortunately no advancement on the pops+cracks issue. Any advice on the next steps?