Matt J. McCullar wrote:
> Well done, John! I know what it's like to fix a "tough dog." Just last
> week I had a _Ms. Pac_ motherboard that turned out to have a bad 2114 RAM --
> it kept cycling through the initial boot-up sequence. I had an external RAM
> tester that said it was okay (of course), but I've seen this sneaky type of
> thing happen before. Substitution nailed it.
>
> You're right about mixing up different manufacturers of RAM chips!
> Guaranteed to cause all manner of weird things to happen.
>
> Matt J. McCullar
> Fort Worth, TX
>
>
This sort of thing - RAM that passes tests by test fixtures, but fails
in the 'real' world - is a pain.
I'm thinking of something that plugs into the CPU socket and after you
'tell' it where the RAM is located allows you to dial up the speed you
want to test it at - or use the system clock. A simple Pass/Fail would
suffice, you figure out which RAM is defective by the allocated space
and if you are testing upper or lower bits (0 - 3, 4 - 7). This could be
used with any static RAM...
First though I'm going to dig out my old Atari RAM/ROM tester
(comparator) and see if it can be used this way - why design something
new when I may have a tool on hand that can be easily modified to do the
job I want? Now to track down my manual - TM-120 is the one for the
Atari Automatic ROM/RAM Tester...probably in the filing cabinets, and I
see no scans posted at the usual suspects.
John :-#)#
(Vancouver, BC, eh?)
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Received on Sun Aug 29 22:35:26 2010
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