Kurt, do you have a scope? I would certainly try reseating any socketed parts. Main rom is socketed for sure. Then I would start at the clock and work forwards. * verify the CPU has clock * verify the CPU control lines are toggling * look at the address and data lines for toggling and level
if that all looks ok then, pin by pin on the main rom, check for toggle and level. again for the ram modules. to make it easy remove as many ram modules as you can. check DC on the power supplies of course. On Fri, May 24, 2019 at 8:41 PM Kurt McCullum <[email protected]> wrote: > I've got two NEC 8201s that are both dead. I'd like to get them up and > running again. Especially the one with the Japanese keyboard. Has anyone > put together a list of what to check to diagnose where the problem might > be. I have done the power supply test from the service manual and the CPU > seems to be correct but I'm not sure where to start. Both units turn on > with a blank screen. > > Kurt >
