Simon Burge writes:
 > Hi folks,
 > 
 > I went to upgrade my pc532 from 8x 1MB SIMMs to 4x 4MB SIMMs, and didn't
 > get any joy.  From what I could tell from the schematics, I should
 > jumper J1 to 1-2 connected for 4MB SIMMs (it's currently 2-3 with 1MB
 > SIMMs).  I tried all four combinations of J1 & J2, before giving up and
 > going back to 8MB total.  It may be bad RAM, or it could be just as
 > simple as not having the right jumpers set up...

	... or it could be a difference between 1MB and 4MB simms :-)

	4MB simms (all?) have something called "JEDEC test mode",
which is entered through a particular combination of transitions on
the WE and OE signals (or something like it). This has been discussed
before on this list. There is a fix that involves a single logic gate,
and another that simply requires some hack & slash activity with a
scalpel and a soldering iron (cut a PCB trace, and add a short length
of wire). This should be in the mail archives somewhere.

 > Unfortunately, I this info isn't in the pc532 FAQ on our webpages, and
 > I can't find my 10-year-oldish pc532 booklet.  Is there anyone who
 > can send me all the jumper (and I guess SIMM) configurations (for all
 > jumpers, and not just the RAM setups) so I can add them to our FAQ?
 > 
 > Related to this, I believe it's simply a case of dropping in a 60MHz
 > crystal in place of the 50MHz one to run your CPU at 30MHz, and a CPU
 > fan is recommended.  Is this true?  I'll add some details of that to the
 > FAQ as well...
 > 
 > Thanks,
 > Simon.
 > --
 > Simon Burge                            <simonb@wasabisystems.com>
 > NetBSD CDs, Support and Service:    http://www.wasabisystems.com/