Need help with Grid 386

Hi, I just picked up a Grid 386 laptop (model 1530) and it has a strange problem. It powers up but dies after a few minutes. It just starts acting flaky and locks up. If you turn it off and back on, the screen stays blank and it beeps but that's all. I have to let it sit for 1/2 hour or so before it works again. It passes all diagnostics before it crashes. I've opened it up and reseated all the removeable ICs. I also checked for overheating but nothing is even getting warm. Does anyone have a copy of the errors that go with the beep code? It has 2 Mb of RAM (8 SIPPs) in it. Which ones are in bank 0 and which ones are in bank 1? This laptop came out of Martin Marietta and has some really cool software on it. It was used to test the gimbal system used for the IR night vision and laser targetting system on the Apache helicopter. The laptop was connected to the gimbal and would read out all the steering commands and the actual positions from the synchro resolvers. This device was a lot more usefull than you would first imagine since cables and connectors that were routed through the gimbal were very prone to intermitant failures and this could be used to pinpoint at exactly what angles the problem occurred. Joe