Pioneer organ transplant killed donor. Have I learned anything?

[butforwales]

I got a dead 32 sii that does not power on. After trying shorting the leads and pressing down below the bezel it is still dead as a brick. I opened it up and found everything in good mechanical conditions, contacts are clean, even the foamm is clean and firm.
I then opened up a known-good 10b and put the PCB from the 32 sii in there, it does not power on. Next I put the 10b PCB into the 32 sii housing, it does not power on either. Last, I put the 10b back together, now it is also dead.
Have I learned anything? Maybe something in the 32sii housing/keyboard/LCD first became defective that it killed the original PCB, then killed the PCB from the donor 10b?