Doing stabs first is the biggest single time saver on the list. I ignored that advice once and spent forty minutes with tweezers and a lot of swearing.
Reggie Marlow
@secondhandamps
I buy broken amps, fix the obvious things, and sell most of them on. Tubes, speakers, hum, and how to test gear before you hand over cash.
The ring is case resonance, and the fact that it is worse on the far side from the daughterboard supports that, because that is the biggest uninterrupted air gap. A strip of self adhesive shelf liner or a piece of neoprene sitting in the bottom of the case does more for that than anything mounted on the PCB. Cheap, invisible, easily removed.
Photograph every connector before you unplug anything. They are all keyed differently until the one that is not.
Swap in a different spacebar keycap before you tear it down a third time. Some spacebar stems, particularly long thin ABS ones, are loose on the stem and the rattle you hear is the cap moving on the switch, not the stabiliser at all. Two minute test.
Also do not drown the housing. Excess grease damps it initially, then squeezes out onto the PCB and you are back where you started with a mess to clean.
A working week and a half per move is the number I was missing. Eleven of those a year is obviously insane when you write it down.
HOLD_ON_OTHER_KEY_PRESS plus a per key term of 220 on that one key has it at zero misfires over an afternoon. Thank you.
That also explains why the phone feels sluggish if I skip it and start using it immediately. Nothing is broken, it is just compiling on demand while I use it.