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Corcomp 9900 MES - Disk Controller + 32K Board Recreation


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34 minutes ago, HOME AUTOMATION said:

I have a pile, all from old hard drives.;)

Understood, I probably do too, somewhere out in deep storage. Getting ready to place a small order to Digikey or Mouser and thought I'd go ahead and get one to see if it fixes my CC  MES. Thanks for responding. I also probably need to change out one of the 22 pin ones  on J2 also, as it appears damaged, though I think it checked out fine when tested 2 years ago.

I think I found them at Digikey, about insulation height .335 inches tall, contact length on post . 126 inches? part # PPPC021LFBN-RC

Edited by RickyDean
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  • 4 months later...

I decided to burn replacement Gal chip for the upper section. I did one at a time, starting with U11, nothing changed. Then I replaced U10 and it woke up some with Extended basic seeing the 32k when you type in size, but none of the ram testers sees the ram. I tried replacing U9, but no change. 

Then I went into the Corcomp peripherial test and it said that on the 32k test:

"Error Found at Address >2010

Value Written = >2010

Value Read + >2000"

Does this sound like a bad TMS4500, though I've changed it out with two other, believed good, 4500's, or bad dram? Or one of the two 9901's bad?

Edited by RickyDean
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I just tried a HXC emulated disk on the MES and it now accesses the drive but I get a disk not intialized message or an error 16 no disk or dosk drive present. These are known good 40 track disk images.

Edited by RickyDean
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