More on bizarre hardware problem

[taob@ionews.io.org (Brian Tao)]

    Thanks to Geoff, Greg, Petar, Eric, David and Bill for e-mailing me
suggestions about fixing the usergroup's GS.  The one thing I didn't
swap was the power supply.  I tried that this morning, and unfortunately
 _ _         _                      _ _    __        _____  ____  _  ___ _ _ 
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| | __|  / _` |/ _ \ / _ \/ __| '_ \/| __|  \ \ /\ / / | | | |_) | ' /| | | |
| | |_  | (_| | (_) |  __/\__ \ | | || |_    \ V  V /| |_| |  _ <| . \|_|_|_|
|_|\__|  \__,_|\___/ \___||___/_| |_| \__|    \_/\_/  \___/|_| \_\_|\_(_|_|_)
                                                                              
(OK, so I think figlet is cool)  :)

    This morning I swapped power supplies between the club's GS and my
own.  With my normal hardware setup (on my system) but with the
supposedly defective power supply, everything boots fine.  This is
with a ProGrappler, a Sonic Blaster, a ZipGS, a RamFAST, my Chinook
4-meg RAM card, my floptical, my hard drive and a 3.5" drive.  The PS
is probably putting out enough juice.  ;-)

    Next I moved the RamFAST over to the club's GS.  The only other
thing in it is a GS-RAM 1.5-meg RAM card.  After turning off DMA on
the RamFAST, I tried booting.  Same results as before (hanging during
boot, or error $110A, or error $0308, etc.  See my previous post). 
This is using the power supply originally in my system.  I tried
plugging in my Chinook RAM card and ProGrappler just for the heck of
it, but of course it still did not work.  Swapped 65816's and ROM's
again, no luck.

    At one point I started getting extremely strange errors after an
OA-Ctrl-Reset.  The screen would sometimes switch to SHR or double
lo-res with some random blocks of pixels repeated across the screen. 
Sometimes the border would turn white and the entire screen would be
shifted up one "border width" and flicker slightly (as if the monitor
frequency was set to 50 Hz, but without the rolling).

    I booted into ProDOS 8 directly (which worked the one time I tried
it) and went into Cat Doctor.  My entire System folder verified
without any errors and the boot partition didn't have any bad blocks
on it.  The GS passed the internal self-test (which makes me question
the usefulness of it).  FTA demos work flawlessly on the club's GS, so
it doesn't appear to be a problem with any of the logic or firmware. 
The Sonic Blaster still works with the FTA demos as well.

    After much discussion with a friend, I suspect that perhaps the
Slotmaker is somehow deficient.  Just on a whim, I looked at memory in
the $C2xx area (where my Sonic Blaster is plugged in).  It read $5B
all the way through, but that's normal.  I was hoping for something
that indicated faulty slots, but I couldn't find it.  Then again, I
was not able to use the RamFAST in any slot.

    The Apple II meeting is going on right now, so obviously I won't
get this darn thing fixed in time.  :(  Sometimes I think computers
are more magical than technological.  :-/

    Any other suggestions?
-- 
Brian Tao:: taob@io.org (Internex Online, 416-363-3783, 27 lines, v.32bis)
::::::::::: 90taobri@wave.scar.utoronto.ca (University of Toronto, 9T4)