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Lancslad43
October 16th, 2007, 03:10 PM
Hi

I have just acquired a PET8032 which appears to work correctly except that on power up it reports there being only 21 bytes free.

Anyone any ideas?

Cheers

Glyn

barythrin
October 16th, 2007, 03:39 PM
I would guess there is probably a faulty RAM DIP (chip) somewhere near the beginning of the onboard memory. The easiest thing to do right now would be to open it up (which is fairly easy but be carefull with the wiring that streches to the monitor (open it slowly to check)) and reseat all the RAM chips and make sure they're in the slots with a good connection and pressed in all the way (not sure what tips folks have for making sure the DIP is in the slot well w/o applying too much pressure to the motherboard yourself).

Lots of system will stop counting RAM once they get to a bad chip (if they're labelled nicely you'll see U04, U05, etc) to identify which order the circuitry goes. If you can tell the capacity of the chips (http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/8032/index.html and maybe main RAM link) you can likely do the math to figure out which chip is bad.

Lancslad43
October 18th, 2007, 03:36 PM
Many thanks Barythrin.

I'll check out the chips to see which are faulty, luckily the equipment to replace faulty ones with socketed chips is available at my work. If I can source replacements I'll replace them all.

80sFreak
October 18th, 2007, 04:20 PM
If I can source replacements I'll replace them all.


http://www.unicornelectronics.com and/or http://www.jameco.com will probably have the static RAM you need.

Cheers,

80sFreak

MikeS
October 18th, 2007, 07:43 PM
AFAIR the video RAM is static (2114?), but main memory is dynamic; shouldn't be too hard to find.

If it works correctly (odd...), why worry? But I suspect that it won't for long...