Re: Apple IIgs random hardware crashing - any ideas?

[grent@comcast.net (Geo3)]

ToasterKing <toasterking@SPLATbigfoot.com> wrote in message news:<161020030242265748%toasterking@SPLATbigfoot.com>...
> Okay, as a follow-up to the totally bizarre behaviour of my ROM 3 IIgs
> as of late, I've stumbled upon something interesting.  Last night I
> completely removed the IIgs motherboard from its case, and reinstalled
> the cards and reconnected the cables with it sitting unhoused on my
> wooden shelf.  Ever since then, it has worked fine.  I used it for a
> few hours last night with SCSI and full acceleration and never had a
> problem.  Since then I've left it repeating the built-in hardware
> self-test for 24.5 hours, and it hasn't failed once.  (Formerly it
> would fail within 15 minutes of repeated tests.)  The funny thing is I
> see no way any part of the board could possibly be shorting to the
> ground shield in the case -- it has more than enough clearance
> everywhere.  I've also tested to be sure that the add-on ports
> installed in break-out panels in the rear of the case (connector for
> SCSI card, jacks for sound card, hyperstudio sound-sampler add-on card)
> and the power supply are not causing ground loops, both by checking
> with an ohmmeter and by disconnecting/removing them.  The GS still has
> crashing problems only when the board is seated in its case.  (The
> board has been removed/reinstalled several times and still this remains
> true.)  I've also tried poking/prodding/thumping the board while out of
> the case and while performing intense operations to see if I could
> invoke a crash, which would indicate I had a cracked trace, cold solder
> joint, or other loose connection, but still it refuses to crash outside
> of the case.  Also, the video corruption I mentioned while running NFC
> Megademo disappears when the GS board is removed from the case.
> 
> Now at least I know my board is okay, but this is driving me crazy! 
> Does anyone have any bright ideas I neglected to consider??
> 
> Many thanks,
> TK
> 
> Original symptoms below for your reference.
> 
> In article <061020030342332489%toasterking@SPLATbigfoot.com>,
> ToasterKing <toasterking@SPLATbigfoot.com> wrote:
> 
> > 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!

Hi,
 Heat maybe causing your problem. The Mother board may have a layer of
dust/dirt on it. Heat plus a little high humidity can cause problems
also.
  A broken wire/ connenction could also cause this. Will be made then
not, equalling high resitance. Might be in the transwarp cable, or
IIgs keyboard connections.
Take Care,
     George