20 May
2014
20 May
'14
2:36 p.m.
The PSU seems to operate fine. I get steady green on the power and can hear
the drive spin up.
It's best not to assume anything (I've wasted hours looking for faults in
one area of a machine ahving assumed another part was correct becuase it
seemed to be, only to find that thet's where the problem really was)
Start with a voltmeter and check each supply votlage at the motehrboard
connector. Also check the power OK line , which I think, should be a TTL
high level when the machine is operational.
If all those are OK, then I would check for activity (toggling) on the
important signals -- the addres and data lines, ROM chip sleect, RaM
address, RAS/ and CAS/ and so on. Jsut to get some idea if anything is
working, This will pick up problems like no CPU clock, or the system
stuck i nthe reset state.,
-tony