Apple IIGS not responding to keyboard

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Apple IIGS not responding to keyboard

Just as the title says. I have an Apple II GS that is not responding to almost any keyboard inputs beyond reset.

Note: for some reason, this board was modified or came with the connectors for a Stealth GS despite being in an original II GS case. 

So far I have tried 3 separate ADB and one //e keyboards with the same results. All keyboards have been tested on other machines with no problems. 

I have been powering this off of an original (not GS) Apple II PSU since the one it came with had a hard drive installed and some of the wires had come loose. I'm in the process of repairing it, but, as mentioned this board was outfitted with the "stealth" connectors so I can still power the computer. 

 

Over all, I have been able to reboot (control-open apple-reset), drop to BASIC (control-reset) and enter the settings panel (control-closed apple-reset). Interestingly, it will respond to the number keys (after repeated presses) in the menue (or at leat it responds to the 1 key), however, the arrow keys continue not to respond. In addition, when in BASIC, random typing will produce spaces, but not consistantly.

 

Additional note: This is a ROM 01 board

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ADB?

The ADB microcontroller UI14 and the ADB GLU chip UI12 are possible suspects. Luckily, there are a large number of test points to make it easy to probe them with an oscilloscope. Since you can get some key presses to be recognized, it seems to be a partial failure.

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robespierre wrote:The ADB
robespierre wrote:

The ADB microcontroller UI14 and the ADB GLU chip UI12 are possible suspects. Luckily, there are a large number of test points to make it easy to probe them with an oscilloscope. Since you can get some key presses to be recognized, it seems to be a partial failure.

Good to know, and I have a scope (mostly working), but the real question is: Can I find a replacement part? Other than from another IIGS.

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Of course, the cause of the

Of course, the cause of the problem may not be the chip itself, but passives or traces around it.

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