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Regel 5: Regel 5:
 
==MM8-EJ==
 
==MM8-EJ==
 
Adresses ending on xxx4 or xxx5 all return zero data, so something is wrong in the adress decoding part or in the stack itself. checking continuity on the X-Y lines of the stack is the first thing to check.
 
Adresses ending on xxx4 or xxx5 all return zero data, so something is wrong in the adress decoding part or in the stack itself. checking continuity on the X-Y lines of the stack is the first thing to check.
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a test with our DSlogic analyzer reveiled a broken 7442 on position E59 and replacing the chip with a spare did the job.
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That was easy...

Versie van 18 apr 2015 20:05

Repairlog PDP8/f

Our PDP8/f seems to have problems with its two corestacks. bank 0-3 are taken care of by a Keronics 812075A, a onr board/two slots memory card. Bank 4-5 is a DEC MM8-EJ 8k cardstack of three cards. As we have the docs for the 8k MM8-EJ stack, we started troubleshooting that one first

MM8-EJ

Adresses ending on xxx4 or xxx5 all return zero data, so something is wrong in the adress decoding part or in the stack itself. checking continuity on the X-Y lines of the stack is the first thing to check.


a test with our DSlogic analyzer reveiled a broken 7442 on position E59 and replacing the chip with a spare did the job.

That was easy...