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Apple IIc shows checkered screen and sometimes "RAM GLU 000101" message after ROM FF upgrade to ROM 00 or later

]uis

New Member
Joined
Nov 24, 2022
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Dear all, I'm cleaning up this IIc + flat display and upgrading its ROM, but while it seems to work fine using the original ROM FF, once I open/short the PCB bridges and use one of the newer ROM versions, the result is a checkered screen (solid squares). Pressing CTRL+Open+Closed+Reset, makes the IIc beep and fills the squares with characters (See attached photos).

At some point, after power cycling the IIc, I ended up with a "RAM GLU 000101" message. I've seen it only once.

Powering on with or without the keyboard installed, results in the same checkered screen. Tried w/ ROM 00, 04 and 4x.

If indeed there's a hardware problem, is it worth finding a diagnostics floppy to execute w/ ROM FF, or should I start replacing the memory chips?

TIA
 

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Just to make sure: you can still go back to the original ROM and the error is gone?

Also note, the keyboard must be connected. With no keyboard, the IIc will not start normally.
 
Sure I can go back to FF. I installed jumper switches instead of soldering the bridge and easily go back to the original ROM. But meanwhile, I've flashed a 32K EPROM with the FF ROM image (16k + 16k appended) which also works fine without touching the jumper switches again. IMO the existing problem isn't related to addressing the bigger ROM.

The 255/FF ROM doesn't have diagnostics and doesn't boot without keyboard neither. Starting from ROM 00, either no keyboard or CTRL+Open Apple+Closed Apple+push and release RESET start the ROM builtin dianostics, which don't work neither in my case (checkered screen/characters).

I don't have or know anyone around (Belgium/Brussels) that could get me a diagnostics floppy to run after booting with the FF ROM. Do you know if I can create such floppy on my Classic connected to the external IIc floppy? This will be my next attempt ... but first I need to fix the Classic too!:p

Btw, the internal IIc floppy is also knackered, somehow. I can only get the "Check Disk Drive" message out of it. I have to drop to monitor and PR#7 to boot from the external floppy drive (I was able to launch AppleWorks this way).
 
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