mpc 1000 freezing - a little differently now

I bought a mint condition yet used MPC1000-BK on ebay a while ago. This is not the BK-N. The seller shipped it with the 128mb of memory that was installed by the dealer, but i think everything else is untouched. After a few weeks of behaving properly, the machine has started to freeze up again after being idle.
This time the screen goes totally blank with or without the CF card in it. I have the latest OS in here. Any suggestions before trying to return it?

return it

Yo man i use to have the exact same problem because the 128 mb i installed was not compatible with my mpc. at first i thought it was because there were no problems straight away but i realized this problems only happen after i upgraded my memory, i just took it out and it works fine. you have to make sure you check what ram chip you put in there

Thanks but I ran some tests, and I think it is a hardware issue. I pulled the RAM and the CF out and plugged it into a different power source. The problem still occurred. When it freezes only a few buttons work, so it's not an LCD issue. This could be a pain in the ass to resolve.