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Sematary
December 28th, 2006, 06:10 AM
The machine runs fine but I get no response from the keyboard. I can play games using the cartridge and all the ports work but for some reason the keyboard is unresponsive. Any ideas?

carlsson
December 28th, 2006, 06:30 AM
Totally dead keyboard? Is it possible to disassemble the computer, in case the cable has come loose? On older computers where the keyboard works, but very poor, it is often worth the trouble to disassemble the keyboard into parts and clean the keycaps, circuit board connectors and rubber plungers (perhaps add new graphite). I've done that with both Commodore and Acorn BBC keyboards, and I suppose most keyboard mechanisms with "real" keys work in similar fashion. It probably won't help you if it doesn't respond at all.

Without looking into schematics, is the keyboard on an 800XL wired through a 6522 VIA or something similar? It could be a such chip that is bad, but I'll let people with actual experience of the computer in question give their expertise.

Edit: In the mean time, you may be interested in this web page: http://www.raphnet.net/divers/atari130xe/index_en.php
Although it is about the 130XE, I suppose parts of it may apply to the 800XL as well, in particular the section that you could try to simulate the keyboard by using a small piece of wire and shortcutting pins on the connector. It means you have to find out what the pinout on the keyboard is like, and from there determine if the fault lies in the actual keyboard mechanism or computer board.

Another link to a past Usenet discussion, of which there may be many over the years:
http://groups.google.ca/group/comp.sys.atari.8bit/browse_thread/thread/2052ad5ad9a09752/6725101df94b021e

Sematary
December 28th, 2006, 09:17 AM
Totally dead keyboard? Is it possible to disassemble the computer, in case the cable has come loose? On older computers where the keyboard works, but very poor, it is often worth the trouble to disassemble the keyboard into parts and clean the keycaps, circuit board connectors and rubber plungers (perhaps add new graphite). I've done that with both Commodore and Acorn BBC keyboards, and I suppose most keyboard mechanisms with "real" keys work in similar fashion. It probably won't help you if it doesn't respond at all.

Without looking into schematics, is the keyboard on an 800XL wired through a 6522 VIA or something similar? It could be a such chip that is bad, but I'll let people with actual experience of the computer in question give their expertise.

Edit: In the mean time, you may be interested in this web page: http://www.raphnet.net/divers/atari130xe/index_en.php
Although it is about the 130XE, I suppose parts of it may apply to the 800XL as well, in particular the section that you could try to simulate the keyboard by using a small piece of wire and shortcutting pins on the connector. It means you have to find out what the pinout on the keyboard is like, and from there determine if the fault lies in the actual keyboard mechanism or computer board.

Another link to a past Usenet discussion, of which there may be many over the years:
http://groups.google.ca/group/comp.sys.atari.8bit/browse_thread/thread/2052ad5ad9a09752/6725101df94b021e


Interesting. You know - my Atari 5200 has a problem with the controllers where they need to be taken apart on occasion and the pathways cleaned with an eraser to rid them of whatever it is that is blocking the signal. This could be a similar situation except with a keyboard. I'll take a look at that first.

Thanks for the reply.

tezza
November 20th, 2007, 11:17 PM
Hi, just ressurecting this thread because I too have an Atari 800XL with a completely dead keyboard! Well, not completely...the Reset works and the Break key gives a line feed but all other keys are as dead as.

I'll take heed of the advice above, but it anyone else has any clues, I'd love to hear them.

carlsson
November 21st, 2007, 01:59 PM
As a side note, I finally own a (fully working) Atari 800XL so I could relate to the procedures explained. On the other hand, I have one more Acorn BBC Master 128 with three dead keys, that eventually I need to solder apart and try to fix.

tezza
November 27th, 2007, 12:00 AM
Thanks to the advice in this particular forum I was able to get my Atari 800XL keyboard working.

It involved unplugging the ribbon (I'm glad someone told me the ribbon comes out naked and the connecter stays on the motherboard...it's not obvious!), unscrewing the keyboard totally and carefully sponging down the keyboard membrane to remove decades of crud which had accumulated there. It took a while and I had to be careful, but the result was a fully working machine!

It was interesting to see how the keyboard actually worked! I didn't realise the keys pressed down on a thin mylar sheet to function.