Re: GS memory problem

[dempson@actrix.gen.nz (David Empson)]

Jim Pendarvis <jpendarv@patriot.net> wrote:

> I picked up a Rom 1 GS this weekend. The memory card is fully populated.
> The control panel recognizes the memory. Running the built-in system test
> ends with "system good".

Unfortunately, the built in test doesn't test the memory expansion card,
only the motherboard RAM.  You will need a separate memory test program
to do it properly.

What brand is the memory expansion card?  Apple never supplied any
memory testing software for their 1MB card, but most third party cards
included test software which were able to show the location of the fault
on a picture of the card.

> But I can't run GS-OS. Sometimes it just beeps and hangs. Other times I
> get an error message (#307?) about trashed memory. A few times I've ended
> up in the monitor. 
> 
> I suspect a memory problem.

Me too.  System error 0308 is one of the classic symptoms of a faulty
chip on your memory expansion card (or some other fault on the card).

It could  be a memory corrupting bug in your system software or an
application, but this isn't very likely.

The other classic symptoms of memory corruption are system errors 0681
and 0682.

Error 0307 ("unsuccessful firmware task") is pretty unlikely to occur,
so I assume you misquoted the number and it was actually 0308 ("damaged
heartbeat queue").

> How can I tell for sure? and how would I identify the problem chip(s)?

A memory tester run for a while should reveal a fault.  The only program
I can suggest off the top of my head is "MemoryTest.CL", which is
supplied with AppleWorks GS.  I seem to recall it being very reliable at
finding faults.

It can pinpoint a fault to a bank number (and might indicate which bit
within the byte is faulty - I don't recall).

Once you have the bank number, you need to identify which physical row
on the card is affected, and which chip within the row.  The best way to
handle this is to get the information from someone else who has the same
card and knows how it is laid out.  If necessary, you can locate the
faulty chip with systematic swapping and rearrangement (assuming there
is only one faulty chip).

It might be as simple as a poor connection between one chip and its
socket - try removing and reinserting all of the RAM chips (observing
the usual antistatic precautions, of course).

-- 
David Empson
dempson@actrix.gen.nz