IBM 5160 oddball fault
jules.richardson99 at gmail.com
Fri Apr 24 18:26:24 CDT 2015
On 04/23/2015 04:55 PM, Jules Richardson wrote:
>> Have you tried the CGA card in different slots? Just in case it's a bad
>> on the edge connector.
> Yes - the same thought had occurred to me.
Aha! I'd tried it in slot six (originally it was in seven) with the same
result, and then I gave it a go in slot five too, just to confirm that it
wasn't 'luck' that two slots were bad - the problem remained.
Now while I had the system board out of the machine (as it makes it easier
to poke around the bus signals without a riser card / extender), I figured
I'd try the other slots just to verify that they were all bad.
Well, it worked in slots 2 and 3 (I didn't try 1 as I've got a hazy memory
telling me there's something different about that one), but was failing in
slots 4 and up.
There was no visible damage to the PCB, but checking with a meter showed
there to be a break in continuity on A11 between slots 3 and 4, so I've now
bridged them with a wire, and all is now working OK :-)
Checking with a meter, it seems that I've got a break in the PCB track for
A11 between slots three and four. There's no visible damage
> I'll take a look at the address lines (albeit just with a DMM, but that
> will hopefully be enough if it's a stuck bit)
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