Re: TWGS Lockup

[nobody@REPLAY.COM (Anonymous)]

nathan@visi.com (Nathan Mates) wrote:
>Phil Abel <TTSH35A@prodigy.com> wrote:
>>It seems that my TWGS will occasionally freeze my GS.  I figure it is the
>>TWGS because I installed it a couple months ago and I never had this
>>problem before.  Is this heat related?
>
>   What's the speed on the TWGS? Going past maybe 10-12Mhz can expose
>lurking flakiness or problems, so you may want to try dropping it. As
>you noted, the problem doesn't appear with the GS's top off, so I'd
>certainly suspect heat.

This may happen, but there may also be a more frequent cause of TWGS
lock ups.  The ribbon cable that connects some model TWGS to the CPU
socket on the GS motherboard was faulty.  When the TWGS is unplugged
and replugged to the motherboard, the faulty cable would cause
intermittent glitches.  AE offered a replacement cable when they were
still around, but now you'll basically have to build one.  It is
a pretty simple operation with parts from Digi-Key.  II Alive had
an article on doing this.

The cable glitch also tends to render the TWGS _more_ succeptable
to heat.  Probably because the heat causes the faulty cable to
expand.  A TWGS with a healthy cable is much more heat resistant.

Thus, heat is the proximal cause, but the underlying problem would
be the cable.  I suspect that with a new cable, the TWGS will be
stable with the top on.

>   The System Saver GS can be opened (6 screws in the bottom under the
>foam) and much more powerful fan installed-- see a local electronics
>supply house for new fans. If you've got access to some drill presses
>or the like, you could always cut some more holes in the SSGS case
>(it's mostly empty space inside) and mount a second fan in there. I
>also found that my system tended to run slightly cooler with the
>monitor not on top of my SSGS, as that helps airflow.

Yes.  The fan in the system saver is a Sprite model SU2C7 and it can
only pull 15 cubic feet of air per minute.  You can drop in a Sprite
model SU2B1, which will move 28 cubic feet of air a minute.  The latter,
although more powerful, is quieter and last longer because it uses
ball bearings. Point your web browser to
http://ground.isca.uiowa.edu/apple2/MiscInfo/Hardware/syssaver.fan
for step by step instructions for doing this.

>   If you didn't have a Vulcan drive and power supply, I'd recommend
>contacting Steve Buggie (buggie@unm.edu) for one of his modified PC
>power supplies that sit outside the GS-- this cuts down on a fairly
>major internal heat source.

Not to mention that a power supply with higher amperage rating tends
to stabilize an accelerator.

-Scott G.