Re: Apple IIgs random hardware crashing - any ideas?

["Jason Whorton" <Please Reply To Newsgroup>]

Hi.  Do you have a spare motherboard to swap in?  Any luck with the CPU and
socket others mentioned?

Thanks,
Jason Whorton
what a comeback by the Colts!

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"ToasterKing" <toasterking@SPLATbigfoot.com> wrote in message
061020030342332489%toasterking@SPLATbigfoot.com">news:061020030342332489%toasterking@SPLATbigfoot.com...
I have a ROM 3 Apple IIgs.  Recently, it was stored in a cardboard box
in a hot attic for about 9 months.  Everything worked well before the
storage.  After being unpacked and reconnected, I'm having strange
stability problems.  Sometimes the IIgs runs perfectly with no
glitches; other times, it crashes every few minutes.  No variables I
can manipulate seem to change the tendency, but sometimes the symptoms
magically go away for no discernable reason.  The problems cannot
always be reproduced, and never occur at a predictable juncture.
Examples of what happens:

o Randomly crashing to the monitor while running GS/OS, an 8-bit
program, or simply pressing Ctrl-OpenApple-Esc at boot time to display
CDA menu
o Occasionally on power-up, a checkerboard pattern on video and no boot
o Occasionally does not recognize SCSI disks
o Hangs in GS/OS with mouse pointer freeze, occasionally with minor
video corruption
o Crashing to the monitor when launching a GS/OS application, copying a
file, emptying Trash, etc. or crashes in ProDOS-8 applications at
random, or when using a system command in BASIC.SYSTEM like "BYE".  A
keyboard freeze sometimes occurs along with this, though the cursor
continues to blink.
o Apple IIgs built-in system test usually completes with "System Good",
but occasionally fails with code 0B030000 (Interrupt test failure on
1/4-second interrupt test) or 093B7200 (ADB failure with checksum
3B72).  The probability of failure always varies, even when all other
environmental variables are kept constant.

In addition, I've also noticed that when running the Ninjaforce
Megademo (patched for ROM 3, and with AppleTalk/IRQ delay on TransWarp
GS disabled as suggested), there is always video corruption on the
lower 1/3 of the display, even though the program may not crash.  I
don't experience video corruption in any other programs unless it's The
symptoms are unaffected by temperature or uptime duration, or by
certain hardware being connected.

Things I have tried, which did not help the problem:
o Removed all cards, including RAM expansion, leaving no external
connections except ADB and composite video out
o Used a different keyboard and mouse
o Turned off nearby electronic equipment that may be causing
interference
o Cleaned pins and reseated all socketed ICs on motherboard
o Checked case for board-to-shield shorts
o Tried different power supply (already 120 Watts), and with and
without spike protector
o Replaced all electrolytic capacitors in power supply
o Replaced electrolytic filter capacitors on IIgs motherboard
o Fattened power supply +5v, +12v, and ground leads
o Fattened power traces on motherboard to slots 3, 5, and 7
o Leaving case open and using a large box fan as cooling
o Checking for any hot ICs
o Disabled TransWarp GS
o Removed TransWarp GS and swapped in original 2.8 MHz 65816
o Set System Speed to Normal

My hardware is set up as follows:
- ROM 3 (1989 revision, 1 MB) motherboard.
- 120 Watt power supply.
- System Saver IIgs on top of the IIgs case
- TransWarp GS accelerator in Slot 3, modified with v1.8 ROM, 14 MHz
Sanyo-designed 65816, 32K cache SRAMs, 40 MHz oscillator for 10 MHz
clock
- Applied Engineering Sonic Blaster GS card in slot 5
- Apple High Speed SCSI card in slot 7.  500 MB hard disk, SyQuest
SQ555 removable cartridge drive, and CD-ROM drive on SCSI bus
(terminated).
- Applied Engineering GS-RAM III populated with 2 MB RAM
- HyperStudio sound digitizer connected to Ensoniq port and fan
connector
- Multiple operating systems on hard disk (System 6.0.1, 5.02, 4.0,
ProDOS 16, ProDOS 8), all used for testing
- AppleTalk is enabled on Slot 1.

If anyone has any ideas or suggestions, they would be graciously
accepted.  Thank you for reading!

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