Help Atari 800 Powers up but KB does not work.

[NML32]

Help, I got a Atari 800 from Craig's list with some other Atari stuff. The 800 boots up to the Memo Pad but none of the KB keys work. Do you think a new KB would fix the problem or could it be the board the KB plugs in to?

 

You may have read my other post about my 800, I plugged the wrong PS in and broke it. Since then I ordered a new 800 PWR board and I am back to the way it was. The KB didn't work before my PS mishap.

 

 

It powers up, I get vedio, I hear sound, Cartridge slot works. Just no typing.

[NML32]

Update: It seems some of the keys are starting to free up.

So far the following keys work.

467WZO;N

 

Is there a safe and easy way to clean the KB.

 

-Mark

[mimo]

just keep pressing the keys repeatedly, that may get them working again

[NML32]

just keep pressing the keys repeatedly, that may get them working again

It has freed up some but there are so many more to go. I think I am going to buy a new one. I found one at B&C for $20.00 new so I think I will go this route.

 

I took the keyboard apart and really didn't see a way to clean it.

 

Thanks,

Mark

[sup8pdct]

How it the keyboard made? If it a type of mylar, clean both the mylar and the rubber under the key, Use contact cleaner. If it is switches, a squirt of contact cleaner may work.

 

 

James

 

 

 

just keep pressing the keys repeatedly, that may get them working again

It has freed up some but there are so many more to go. I think I am going to buy a new one. I found one at B&C for $20.00 new so I think I will go this route.

 

I took the keyboard apart and really didn't see a way to clean it.

 

Thanks,

Mark

[re-atari]

How it the keyboard made? If it a type of mylar, clean both the mylar and the rubber under the key, Use contact cleaner. If it is switches, a squirt of contact cleaner may work.

Contrary to the XL-series, the 800's keyboard does not contain a mylar sheet but is built up from real switches on a PCB.

 

Reseating the connector on the rainbow flatcable leading from this PCB to the mainboard might be a way to get it going again. If the computer has been stored in a damp garage, it might also be a case of corroded contacts inside the switches. The error description suggests this is the case. Contact spray should be able to deal with this. Carefully pry off the keycaps (after writing down the layout of the keyboard) to gain access to the actual switches and spray a little bit on the contacts. After reassembly press the keys repeatedly to wipe off any remaining oxidation. They should start to work now.

If that doesn't get the keyboard working, resoldering its PCB is the only remaining option.

 

re-atari

[NML32]

How it the keyboard made? If it a type of mylar, clean both the mylar and the rubber under the key, Use contact cleaner. If it is switches, a squirt of contact cleaner may work.

Contrary to the XL-series, the 800's keyboard does not contain a mylar sheet but is built up from real switches on a PCB.

 

Reseating the connector on the rainbow flatcable leading from this PCB to the mainboard might be a way to get it going again. If the computer has been stored in a damp garage, it might also be a case of corroded contacts inside the switches. The error description suggests this is the case. Contact spray should be able to deal with this. Carefully pry off the keycaps (after writing down the layout of the keyboard) to gain access to the actual switches and spray a little bit on the contacts. After reassembly press the keys repeatedly to wipe off any remaining oxidation. They should start to work now.

If that doesn't get the keyboard working, resoldering its PCB is the only remaining option.

 

re-atari

 

I took the back off of the KB about 16 tiny screws and it appeared that the keys pressed a little rubber pad aginst what looks like a mylar contact.

Edited July 1, 2009 by NML32

[re-atari]

I took the back off of the KB about 16 tiny screws and it appeared that the keys pressed a little rubber pad aginst what looks like a mylar contact.

That's strange, AFAIK mylar sheeted KB's were only used on 800XL's (white with dark brown casing), but not on the original 800's (beige typewriter-like casing). When trying to clean my 800 I couldn't disassemble its KB beyond removing the keycaps. I'm pretty convinced the KB didn't have 16 screws on the bottom plate, that sounds more like a 800XL KB to me.

If your mylar sheet is at fault, fixing it permanently will prove difficult. A minor scratch in the traces can be repaired with conductive paint, but I doubt it will last very long. Another possible cause for your trouble could be that the KB decoder IC's (2x CD4050) have corroded or just dirty contacts in their sockets. Prying them out and reseating, and perhaps swapping them, should rule this out as a possible cause. Handle them with care, they are CMOS and hence very sensitive to static electricity. And, of course, make sure you put them in correctly (check the pin 1 orientation).

 

re-atari

[sup8pdct]

That is how my 800 keyboard is. Tho cannot remember how it worked.

When I come back from my holidays (6 weeks) will take mine apart and take some pictures, unless someone beats me to it.

 

James

 

 

I took the back off of the KB about 16 tiny screws and it appeared that the keys pressed a little rubber pad aginst what looks like a mylar contact.

[bbildakid]

Keyboards can go in the dishwasher FYI....

 

It was even on my A+ Cert exam heh.

[bbildakid]

http://www.boingboing.net/2005/05/30/clean...-keyboard-.html