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I've just started work to restore a C8P-DF (without the 8" drives) that looks to be in great (cosmetic) shape. Removed the 5 boards (505B, 540B, 2x520, 1x527), checked traces and seating of IC's, and dusted off the boards. The power supply has two sets of outputs and the voltmeter shows both are generating good voltages and currents. Have reinstalled the boards and am preparing to power up the system.

Noted that the front (lit white plastic square) power button does not appear to be a power button. I'm assuming it is just a reset switch.

Question: should this system work with 5.25 drives if I swap out the existing A-12 board for an A-13 board configured for use with 5.25" drives?

I believe the lighted switch is indeed a reset switch. You can verify that with an ohmmeter. It should plug into the molex connector at the top of the 505 board.

This system can use a 5.25" drive, but you will need to jumper the clock divider U6D for 125 kHz instead of 250 kHz, and also adjust the time one-shot constants for 5.25" floppies.

Or, you can use a 3.5" floppy using the same hardware and software configuration as the 8" floppy.

Good luck with the restoration!

Dave