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PDP8/M M8650 Problem


Experienced Member
Apr 2, 2014
Dordrecht , Netherlands
AC is clear and completely zero.
The program does in RUN not halt.
The 'random" AC I mean in RUN state all AC lights are randomly flashing,
In step mode we see what is happening on that AC.That conclude that.

There is in your prog in step mode a kind of increment to be noticed.

Indeed something serious must be done with this card.
Thing is ,I took out app 90% of the Logic to test on a breadboard separately from the M8650.
Replaced app 5 IC.s that were definitively bad.

As I have it running that close to a finish now it just keeps in mind there should be just 1 more logic that at this point
not function quit as it should.

Think I go replace logic just around that C0 C1 and see what come out of it.
May be in the end I just go for a complete refit.

Next is also a good practise to get to know how the card is actually working.

As I have other cards before that indeed had a failure, mostly 1 or 2 logic replace and back in business.
Also I repair in hobby as in business all kinds of electronics.
Computer,Radar, navigation equipment, old tube Radio's, Pinball machines, old huge diesel engines, you name it and I ..mostly... can fix it.

This card how ever....

I'll be back.

Thanks for now,