I've picked up an early 2001-8, which was the computer I had as a very young child. I'm excited to restore it - I've started with the power supply, keyboard and mainboard before I move to the high voltage or cassette. I replaced the fuse holder and confirmed the voltages. The keyboard was repaired with conductive paint. The machine boots with 1K of memory - no surprise there as there are some missing chips and clearly some bad 2114s.
I have a PET video out until I get to the monitor repair, and a Tynemouth RAM/ROM replacement, so the onboard RAM issues shouldn't present a problem.
Running the PET Tester ROM from the RAM/ROM board shows a full screen of correct characters, so I assume the character ROM and all video memory is working correctly? [image attached]
Running any simple programs such as Maze or short programs I write work just fine. But running more complex programs like Pet Invaders or Attack of the PETSCII Robots have character corruption, shown in the images.
Any thoughts on where to begin troubleshooting? Thanks.
I have a PET video out until I get to the monitor repair, and a Tynemouth RAM/ROM replacement, so the onboard RAM issues shouldn't present a problem.
Running the PET Tester ROM from the RAM/ROM board shows a full screen of correct characters, so I assume the character ROM and all video memory is working correctly? [image attached]
Running any simple programs such as Maze or short programs I write work just fine. But running more complex programs like Pet Invaders or Attack of the PETSCII Robots have character corruption, shown in the images.
Any thoughts on where to begin troubleshooting? Thanks.
