I am working on a Falcon, and discovered yesterday that it was crashing, complete with screen flicker, whenever I inserted a floppy. It quickly became clear to me that it had nothing to do with the floppy drive, but with the physical shock to the board from inserting the floppy. I was hoping that there was a simple short to the shielding happening somewhere, but unfortunately this seems not to be the case.
When it crashes, I get one frame of bad video, then the desktop returns to normal, but with the system frozen...
One such frame. (The whole display is changing to the garbage pattern. The desktop is still visible because my camera isn't in sync with the display.)
I have stripped the system down to the bare board, and it will fairly consistently crash if I let it warm up (it does not crash cold) and then tap lightly with my finger on various ICs, to send little shockwaves through the board. (Don't worry, I'm talking about quite light tapping here, nothing that should cause any problems on its own.)
There is no HDD present, no floppy present, and I've changed the RAM and PSU both to eliminate these factors. No change.
Sadly, I think this may point to microfractures in the board. I have visually inspected with a magnifier and don't see anything, but of course it doesn't take a visible crack on a multilayer PCB to cause problems.
One other thing about this board... When looking at the bottom, I saw this unusual capacitor arrangement...
I don't think I've ever looked at the solder side of a Falcon board before, and I don't find any pictures of it online either, so I have no idea if this is typical or unusual.
Does anyone have any thoughts on the crashing problem, or remarks on the capacitors? This board is starting to make me sad.
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