ROM/RAM board to identify the faulty ROM and RAM chips. The latest version allows me to test individual ROMs (or pairs or ROMs). From this, four of the seven ROMs were bad.
- Faulty ROM and RAM - replaced by ROM/RAM board
- Faulty CPU - replaced with NOS 6502
- Faulty keyboard VIA - replaced by WDC 65C21N
- Damaged TIP29s - replaced by NOS TIP29
- Partly faulty character ROM - replaced by 2716 EPROM and adapter
- Faulty video RAM - replaced by 6550s from main RAM
- Soldered on power cable - replaced by plug and socket and new wiring harness