I am working on my first restoration project, a Compaq Portable (not my first choice, but it was a steal!) with 256k total in RAM. I have replaced all the electrolytic capacitors in the power supply, and the CRT, And have replaced the foam pads in the keyboard. However, every time I start it, it gives me the error code 0020 201. It has banks 0-3 filled with 64kx1 RAM chips, so I think it is U45, however I can't for the life of me find it! I have made sure that all the connections are good, and all the ram chips have been socketed. Any help would be great!