Re: IIGS memory error

[Wayne Stewart <waynes@intergate.ca>]

"ground.ecn AppleII Librarian" wrote:
> 
> When I run the Claris memory test (MemoryCL) from AWGS on a Rom3 with 1Meg
> Apple memory expansion board, I get a memory error at $180582 .
> 
> Which chip(s) is most likely at fault.  UA1-UA8 are soldered in.  UA9-UA16
> and UB1-UB16 are socketed.  UA1-UA16 are top row of memory chips, UB1-UB16
> are bottom row.
> 
> I was guessing a chip around the UB9 socket but moving around
> chips in UB8-UB11 isn't helping.  Removing UB9 chip doesn't even let the
> GS finish booting Sys6.0.1.
> 
> What are stategies for finding/isolating bad chip?  Once I find the right
> group of 8 chips I think I can shift and rotate to find bad chip but I
> can't find the right place to start yet.

I have no idea which chip it is. However your IIgs should have no
difficulty shift-booting even without the memory card.
I'd remove the top jumper on the memory card which will cut off access 
to the bottom two banks, shift boot and try the test again. If it passes
you know it's on the bottom 16 chips, if not pull the bottom jumper
and run the test again. Don't forget to shut down the IIgs before 
pulling that jumper! 
Hopefully it starts passing before you pull the card and get down to 
testing the motherboard RAM.

	Wayne