Re: Crashes with ZipGSX

[dempson@actrix.gen.nz (David Empson)]

SteveC1021 <stevec1021@aol.com> wrote:

> I have a ROM 01 IIGS with a 9 MHz, 32K ZipGSX. It has been running fine
> for over a year, but lately has started crashing within a few minutes of
> booting up...it doesn not crash, however, if I use the CDA to turn off the
> Zip.

We might have a fault in common.  My first ZIPGS card worked fine for a
year, then started getting progressively worse.  It was in my ROM 1 at
the time, and it eventually got so bad that I had to remove it.  I
subsequently bought a ROM 3, and tried the ZIPGS in it: it worked fine
for a while, but again degenerated and became useless over time.

I then got hold of another ZIPGS and it has been working fine for the
last three years.

[I had a vague plan to try to resurrect the original card by replacing
components until I located the fault, but never had any particular
reason to do so, because I hardly ever use the ROM 1 IIgs any more.]


Do you use text-based programs on a regular basis?  If so, did you
happen to notice strange display problems?  One of the first symptoms I
saw on my faulty ZIP was that the text screen didn't scroll properly -
characters appeared to be left behind, implying that writes were not
getting through to the computer's memory.

The most common fault at later stages was a random crash into the
monitor.

It appeared to be a temperature related fault, because the computer
worked fine for several minutes after being switched on.  It then went
through a period during it would keep crashing, but after an hour or so
it would work reliably again.  (I think it eventually got to the point
where it never worked reliably, but I haven't used that card for at
least three years, so my memory is a little hazy.)

> Any ideas? Could this be a power problem? I do still have the stock power
> supply in this computer, as well as a RamFAST, AudioAnimator, and Quickie
> card. I've been meaning to buy one of the Buggie power supplies. Is this
> the push I need?

Could be.

One thought that comes to mind: has your ZIP been modified to provide a
higher voltage to the CPU?  This was done on my second ZIP (as supplied)
but not on the first one.

This modification involves several components around the "Q2"
transistor-like device near the slot connector (at the bottom of the
card directly under the leftmost RAM chip).  This area was unpopulated
on my original card.

This circuitry derives a supply voltage of about 5.3V from the 12V rail
through an adjustable regulator (Q2).  The extra voltage allows the CPU
to run more reliably at higher speeds (especially at speeds higher than
its printed rating - my second card has a 7 MHz CPU clocked at 8 MHz).

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand