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This is the third part in the Commodore 128 repair. Initially, the whole system was dead, but now, the power supply has been fixed. After that. some keys were not working, which was resolved when the keyboard was refurbished. The mainboard has been cleaned and checked over, and there doesn't seem to be anything wrong with it.
Commodore 64 Diagnostic Cartridge and Test Harness.
try out all the modes.