If anyone here is familiar with diagnosing issues on the TranswarpGS:
I installed my TWGS card in two different GS systems, a Rom 0, and a ROM 1. Both present me with the same issue.
I'm attaching photos of what I see on the display. Please advise if you may know how to determine the cause of the fault.
I have a little experience with repairs.
First I'd ask if you have fully rebuilt or replaced your PSUs? There's a chance that could be the issue. If you need a PSU for testing here's a link. Get a Universal PSU Kit and update or just get a whole new Ultimate Universal Power Supply. You could also send in your PSU for upgrade with our Power Supply Rebuild service if you're not very handy. https://www.reactivemicro.com/product-category/power_supply/
Next, is the CPU Cable original? Then that could be the issue. Those original cables were made to be broken. Very low quality. Get a new one for main use and retire the old cable. Here's a link: https://www.reactivemicro.com/product-category/apple2/iigs/transwarp-gs/
Assuming however it's not those two things, reseat the Oscillator and Cache Card. Power on a few times to check. If that doesn't do anything then try to 'twist' the card slightly, and while applying pressure turn on the IIgs. Hold pressure when on. See if it helps or if anything changes. If not, twist the other way and repeat.
If all else fails, reseat the GALs. If you have an IC Programmer you could reprogram the ICs just to see if that helps. It's rare but sometimes a GAL does fail or suffer from bitrot.
After that it might be a lost cause. I can take a look at the board locally, but repairing a stubborn board can cost as much as a new one. I could however have a look and at least let you know if it's worth the repair. With some luck I might be able to fix it within an hour or two and keep it under $100. If not I'd recommend just retiring the board and get a new one for years of trouble free service. Here's a link:
Hope that helps
WIth a new cable and a 32K cache card from Creative Micro, as well as a 28MHz Xtal that Henry supplied, my old Transwarp card lives anew.
Thank you Henry!