Re: Help me restore my //c to working order!

["Bill Garber" <willy46pa@comcast.net>]

"Osgeld" <osgeld@cheesefactory.us> wrote in message bb7033fb-d261-4eb0-bed4-8a40578c114e@o8g2000prf.googlegroups.com">news:bb7033fb-d261-4eb0-bed4-8a40578c114e@o8g2000prf.googlegroups.com...
On May 10, 9:27 am, "Bill Garber" <willy4...@comcast.net> wrote:
> "Andrew Croney" <ab...@mtmail.mtsu.edu> wrote in
> messagenews:iqahi6$o2j$1@speranza.aioe.org...
>
> > I recently powered on my //c after a couple months of inactivity, and
> > noticed that I couldn't even seem to load ProDOS without the system
> > crashing. After a self-test I got RAM errors. I assume a RAM chip has
> > gone bad, but I've never had to do any repair on it so I have no idea
> > where to begin. There's an error code for the self-test, but it's
> > different every time so I don't know how I would determine which chip
> > needs replacing. Here's some samples:
> > RAM 0 1 1 1 0 0 0 0
> > RAM 0 1 1 0 0 1 1 0
> > RAM 0 0 1 1 0 0 0 0
> > It's summer break and I have plenty of free time, so hopefully I can get
> > it up and running and play Oregon Trail again. XD
>>
>> I'd say that if you are getting a different RAM error each time that
>> it's not a DRAM itself, but possibly a loose connection on the MMU,
>> Memory Management Unit, or even the CPU. If these are socketed, you
>> might try lifting them slightly and pressing them back down to score
>> the pins so that they make better contact. This is one of the pitfalls
>> of socketed ICs after they sit around for a time. Let us know how you
>> make out. :)
>>
>> Bill
>
> I agree remove and re-seat any socketed chips, though there
> is only a few in a //c.

I've seen IIc versions with CPU, IOU, MMU, and all DRAM socketed,
and all variances in between, down to just the CPU. I think I even
saw one with all chips soldered in. Not for long, as I removed and
socketed the CPU, IOU, and MMU, but only DRAM as needing replacement.
No point heating them up when they work.  :)

Bill