/diy/ - Do It Yourself

Sup /ohm/, think I just made a pretty gutting discovery.

Pic related is the mainboard of a Commodore 8032, deader than fuck. I have been trying to establish the power rails at least are present but this is the only schematic I can find for the board and there are some different part numbers on the schemo vs the board.

1. Does anyone know of a good lookup site for substitute regs? I remember back in the day doing electronics in high school we had thick arse books full of substitution tables. All I am finding in google is guides on what parameters you need to cross check, breakdown voltages, Pd, Ic etc. as opposed to a "plug in part number, receive substitute p/n" kind of gig. I want to make sure the 7805's are equivalent to the 304-5's and aren't a bad hack by the previous owner (unit came from a ham shack at a deceased estate and shows all sorts of signs of customisation, including a new row of keys above the factory one for RTTY functions)

2. I bypassed the rectifiers and am injecting 9V @ 30mA while I test, enough to run the regs but not enough to let smoke out of the chipset if shit is wobbly. I am however seeing 9VDC on the output of these regulators, which constitutes the gutting discovery. If that is the case all components on the board have likely copped 22VDC/2A unregulated to their VCC from the factory power supply, which is of course the equivalent of a nuke from orbit. All three are exhibiting this behavior however. I would consider it highly unlikely that all three could fail in the same manner unless they somehow break down internally after 20 years of doing fuck all? I seem to recall as I was learning about electronics in the late 90's that TO-3 package regulators could catastrophically shit the bed in this manner and were to be avoided like the plague for TO-220 packages if possible when designing/building, can anyone verify any this?