As part of my repair series on the Europlus, the next step I'm taking to investigate the "screen full of question marks" is to ensure the ROMs are working, valid chips.

As before, I decided to use my TL866II to dump the ROMs, with suitable mapping of pins between the ROMs, and a similar ROM that t...

The Apple II Europlus uses 4116 type RAM ICs.

On my board, there were about 4 different manufacturers and speeds - obviously some have failed in the past and have been replaced. Without a booting machine however, how can I test that the RAM is working OK?

Thankfully, a circuit for testing 4164 I...

As part of the repair process for the Apple II Europlus, I have been testing each IC on the motherboard, to ensure it is working correctly. I have been able to test many of the 74 series ICs with my Xgemu 866 Universal Programmer, but there are some ICs that require more complex circuits to test tha...