Looking for advice on a hanging IIGS

3 posts / 0 new
Last post
Offline
Last seen: 3 days 19 hours ago
Joined: Jul 25 2018 - 23:41
Looking for advice on a hanging IIGS

Hello,
I’ve been trying to diagnose a hanging IIGS.

Symptoms:
After 30mins of play, my IIGS hangs. The screen freezes and a ctrl-Apple-reset goes to a black screen, no boot sound. It never drops to monitor like I think a random crash should do. When I power off and on, the screen shows colored checker board. After sitting off for 10-15 minutes it works again. This is with the chassis closed, and display on top, e.g. hottest config.

With monitor on the side, and chassis open, it never hangs, it has to be an overheating problem. My first thought is PSU.

I reproduced the hang, then immediately opened the chassis to test voltages. I left it on and underload to get a good measurement. Everything looks ok. -5v was a little high at -5.20v, and comes back down to -5.12v after cooling off. Is this enough to crash a iigs? Is it really the PSU?

I also used an oscilloscope to test for noisey DC, but it looks clean.

Any other ideas? All the bus slots are empty. Only card in the machine is a GGlabs 8MB expansion in the memory expansion slot. Next thing I’m going to try is pulling the memory expansion, or running a memory test.

Taxonomy upgrade extras: 
Offline
Last seen: 1 day 21 min ago
Joined: Dec 3 2015 - 20:45
sounds like the 65816 itself

sounds like the 65816 itself is stopping. you could put an ice cube in a ziplock back to seal it
then when it locks, hold it on the chip a few seconds then try ctrl-Apple-reset to see if it starts again.
You could try cooling the other chips as well.

Larry G

Offline
Last seen: 3 days 19 hours ago
Joined: Jul 25 2018 - 23:41
Thanks, I ordered a new PSU

Thanks, I ordered a new PSU before your reply, but it hasn’t come
Yet.
I tried your suggestion yesterday, but couldn’t get the computer to hang. Another thing I did was finally cut out the old dead battery (ROM 01), but that shouldn’t be related to any freezing.

Log in or register to post comments