Sx-64

Spot the difference. Before: After: The former owner replaced the original SX-64 KERNAL (251104-04) with a C64 one (901227-02), most probably to be 100% compatible with all the games. But an SX-64 doesn’t feel like an SX-64 without its unique colors. That’s why I replaced the KERNAL chip again, this time with the original one. Actually I couldn’t find the original chip (the MOS 251104-04) anywhere, so instead, I installed an EPROM chip with the original SX-64 KERNAL programmed into it. ...

MOS 6526: The CIA chip You turn on your beloved SX-64 and you don’t see the blinking cursor. Don’t panic. Most probably one of the CIA chips (MOS 6526) is not working correctly. No blinking cursor. The Commodore 64 has two CIA chips. What you need to do is to replace the one that controls the keyboard, the CIA 1. But if you don’t know which one is CIA 1 and which is CIA 2, then you can either replace both, or do trial-and-error, or look at the IO schematics (hint: it is the one with the UB3 legend). ...