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linemanduke
March 21st, 2006, 10:22 PM
i have an atari 800 and only a handful of the keys function at the moment i think their esc, space, caps lower, 3, 6, and h. how do i fix this all contacts are clean and i took the bord out and checked with ohm meter every key showed continuity when pressed . what do i do?

NathanAllan
March 22nd, 2006, 06:00 AM
Have you checked the conector the the mainboard? Any loose wires? Are there any controller chips on the keyboard underside that can be reseated? Are there any chips on the mainboard that can be reseated? Is the keyboard getting enough power? Those are the key things that can go wrong with my st, some of them may correspond to problems with the 800. Hope this helps.

nathan

linemanduke
March 22nd, 2006, 12:00 PM
there are no chips on the key board the connector & cable show continuity there is a dark spot kinda purple incolor on the connector and wire like it was burned? unsure about chips on board have to check.

linemanduke
March 22nd, 2006, 12:01 PM
how do i check if theres enough power?:confused:

NathanAllan
March 22nd, 2006, 06:32 PM
Have you looked up the schematics for that 800? I know they've got to be out there somewhere, and one of the pins is a power line for it.

Does anyone here have an 800 and can assist???

I'd like to say go ahead and check the outputs of the ps, but I doubt it'll do any good. No burnt smells coming from it? Does that burned-looking place feel gritty and dusty? I don't have am 800 or any documentation, so I have a bunch of questions too :?:

linemanduke
March 22nd, 2006, 08:11 PM
it was sharpie:rolleyes:mathes an identical spot on board "to tell correct orientation of connector"

have no schematics but looking found that most of the working keys are first ones that go to the connector. i don't know if this means anything but when i hit the keys that do work the internal speaker lets out beeps like when your modern computer freezes its probably suposed to do this but better safe than sorry

linemanduke
March 22nd, 2006, 08:35 PM
found some schematics at http://homepage.ntlworld.com/kryten_droid/Atari/800XL/atari_hw/atari_hw_contents.htm im unsure of helpfulness of them so suggestions are appriciated

ahm
March 23rd, 2006, 10:49 AM
Have you tried taking the keyboard apart?

When I first got my 800XL, one of the keys was stuck on
and I was able to disassemble the keyboard fairly easily and fix it.
The actual switching is done by two sheets of plastic with conductors
on them. By lifting each sheet and carefully wiping them with a dry
paper towel, I was able to remove whatever it was the was shorting
the one key. I imagine the 800 has a similar arrangement, but of course,
"your mileage may vary". :-)

Good luck,
Andy

Micom 2000
March 27th, 2006, 10:35 AM
I believe the Atari 8-bit faq had a section on power supplies. Search on the Google newsgroups in
comp.sys.atari.8bit

Lawrence

linemanduke
March 27th, 2006, 03:17 PM
checked voltage at pin 16 on two indenticle ic that the key boards feed into voltage came in at 4.5 volts compared to the 5v its suppused to get checked every test point on the power and mother board all 5v points tested as 4.5 and all 12v came as 11-11.5v the key board after the first set of keys on each circut test at what looks like 2.2v and 1.0-0v after that had the idea to switch the two ic the key board feeds into since they had the same part number and ended up with a totally new set of keys working only one that worked before stayed working and that was the esc key in the whole process of put the thing back in its case i broke 2 leads of the key board and will probably fix it tomarrow

linemanduke
March 21st, 2007, 03:56 PM
well the atri got side tracked for a while but im finaly working on it again. i replaced all the electrolytic capacitors which brought the voltages to spec but now the keyboard still wont work right. so i think im just gonna have to find a new set of the chips thart control the keyboard i also need a new keybord as the traces are lifting off of this one. anyone know whaere i can get these?

linemanduke
March 27th, 2007, 03:34 PM
i got a set of chips from a source today and put them in soldered back the keybord and ITS ALIVE mostly i have two disk drive and only one works other just sits there andf spins any suggestions

Terry Yager
March 27th, 2007, 04:23 PM
i got a set of chips from a source today and put them in soldered back the keybord and ITS ALIVE mostly i have two disk drive and only one works other just sits there andf spins any suggestions

Ummn, addressing jumpers? This should keep ya busy for awhile:

http://www.myatari.net/forum/read.php?1,2603,2627

--T

linemanduke
March 28th, 2007, 12:10 PM
no that wasnt the problem busy light stiul wont turn off and it jusyt keeps spinning its an 810 model drive the kind with the small slot not the big door

linemanduke
March 28th, 2007, 12:49 PM
well by switching out bords ive narrowed it down to the side board so i guess ill start switching out chips unless someone knows where to get one complete board