Rominator not working?

[JustDaveIII]

I bought the Rominator for my 128k motherboard. I have the 820-0086-C board. Although I've checked every signal (rom address & data pins to cpu pins + ROM.E) and the A17-A19 address & R/W jumper wires. I don't get any boot beep and after 5-8 or so seconds I get a checkerboard video.

I don't have a rom reader but I did breadboard a manual one where I checked the first 4 words in each rom and they looked good. In a few days I'll have a 512k board to try it on. With my cheap-o logic analyzer I see data / address changing on every rom pin.

I read that my board is missing a later modification. That being some resistor network on the VIA. Do you know what pins on the VIA got the resistor network?

Any thoughts as to why my Rominator isn't working on the 820-0086-C board?

 

[Builder68]

A checkerboard screen usually indicates a communication failure between the CPU and ROM, most often caused by a poor mechanical connection.

The original ROM sockets were designed for flat DIP legs and are known for losing tension and wearing out easily, so the Rominator’s pin headers often fail to make solid contact. Try cleaning the sockets with DeoxIT or a similar contact cleaner.