Today’s pickup - “portable” IIgs setup - help needed

wottle

Active Tinkerer
Oct 30, 2021
814
563
93
48
Fort Mill, SC
Today, even though I’m trying to downsize my collection, I ended up picking up an apple IIgs that is a ROM 01 machine and looked to have a box full of accessories. The main reason I got it was because it had the original Apple desktop bus keyboard, which I’ve always wanted to add to my keyboard collection.

When I arrived to pick it up, the man who is selling, it had it in a box, and I thought I was just gonna take the computer out of the box, but he said the box was actually designed specifically to transport a IIgs that he had had since he had the machine original, and worked in the telecom industry. It fit the IIgs, the Apple color monitor, the 5.25 inch and 3.5 inch floppy drives, and the keyboard. Looks to be made by a company in Columbus, Ohio, but he said he was living in California at the time.

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The other good news is that it had some very cool cars and accessories. Inside was a 4MB GS Juice memory expansion card. It also has a ZipGS GSX accelerator card. Looks like it plugs into an expansion slot and then a ribbon cable plugs into the cpu socket.
In the box of accessories there was a ZipDrive hard drive card and anSonicBlaster sound card. As well as a cool handheld scanner and interface card called a Vitesse Quickie.
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Now the bad news. While the seller showed a picture of it booting to a IIgs blue boot screen, I have not had any luck getting it to show anything but a weird black and white pattern on the screen.

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It doesn’t seem like doing a reset does anything helpful. Any ideas on where I need to start? I verified the dip switches were correct on the accelerator card. And I tried with and without the memory expansion card. I haven’t tested the PSU voltages yet but will do so. I also can’t test without the accelerator because I don’t have the original CPU.
Appreciate any advice y’all can give. I’ll try to take some better pictures of the case when I get the chance.
 

Volvo242GT

Tinkerer
Feb 7, 2022
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Currently Duvall, WA
I'm guessing it won't go into the self-test mode, by holding down the option and command keys while turning it on? If you can get it to do that, we might be able to see what's going on. I'm assuming that you don't get the usual *Dernk* startup chime when the power switch is flipped on?
 

wottle

Active Tinkerer
Oct 30, 2021
814
563
93
48
Fort Mill, SC
Sorry, I forgot to mention that. Yes, not startup sound at all. And won’t go into self test mode.

I cleaned the board and replaced 4 caps that I had replacements for on hand. No change.

I pulled out my known working IIgs and decided to confirm the ROM and CPU accelerator were working, and they do. When I put the known good stock CPU and ROM, I get the checkerboard pattern still. Also swapped out the other socketed chip - 343-0051. I also swapped in a recapped PSU, even though the voltages looked good, just to be safe. No change. So it's definitely something else on the main board. I'm going to take a closer look at the sockets - maybe the ROM or CPU sockets are bad, but that seems unlikely.

It seems as thought the reset pin (pin 40 on the CPU is being held high, which I believe it wrong. I see it briefly drop when I hit reset on the keyboard.
 
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