Transwarp GS failure mystery

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Last seen: 1 day 19 hours ago
Joined: Jan 23 2022 - 16:34
Posts: 9
Transwarp GS failure mystery


I would like to solve a mystery regarding Transwarp GS failure.

One day, I powered on my ROM03 IIgs and the screen was frozen with rows of mixed colours (green / grey).

My TWGS was upgraded with new GAL and overclocked up to 12.5Mhz. I even tried to restore it to stock speed, without any lucks

Then I've replaced the PSU and the CPU cable I've ordered from ReactiveMicro : by miracle my Transwarp worked correctly.

I would like to understand how this failure had occurred ? The CPU ribbon was already replaced ages ago.

Could be possible that the CPU ribbon was the problem, or the original PSU, or both of them ?

Many thanks for your insights.

Last seen: 38 min 12 sec ago
Joined: Jul 5 2018 - 09:44
Posts: 2461
If your old PS wasn't

If your old PS wasn't supplying the right voltages, it can cause all sorts of weird behavior including startup failures like your pic.  TWGS and given that vintage card, I assume you may also  have a traditonal RAM card like the Apple one or an AE one that uses lots of chips...  those kinds of cards suck down LOTS of joice.  Even a power supply that might work fine in a bare machine can sometimes be weak enough to have voltage "sag" when in a heavily loaded machine.  FWIW, one of the newer RAM cards like the Garrett's Workshop one that use a small chip could and lower powered RAM chips can be a huge win in power supply life and also less heat.



Last seen: 1 day 19 hours ago
Joined: Jan 23 2022 - 16:34
Posts: 9
IIgs setup

Thank you very much for your answer !


Indeed, I should have specified the actual functional setup of my IIgs machine :

- ROM03

- 12.5 Mhz TWGS with firmware 1.8s and 32Kb cache

- CFFA3000

- ByteBoosters 4Mb RAM

Prior the failure, this machine had Unternet card. I've removed it now as it was fallen into disuse.

Nothing of special, I'd say. The last setup was stable during around 4-5 years before the incident - I'm a bit puzzled.


Afterwards the original PSU could be the culprit as it was on original condition since 30 years : it's the best time to change it...


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