Atari 800 keyboard issue

[High Caliber]

Hey guys, wondering if you have any idea here.  

 

I recently recapped my atari, it had a few weird issues that the re-cap took care of.  All good, except the esc, 1, tab, Q keys don't work.  

Now this isn't a mylar keyboard, it's a weird one with yellow plastic caps, and brass contacts that come together when the key is pressed.  I've sort of eyeballed my connections and of course double checked the caps, but figured it might be worth asking here.  Thing is, I didn't test all the keys before the recap, so not sure if it's a new issue or something that had developed.  Almost all of the key 'cups' had split, and the keys just fell out when I flipped the computer upside down.  Terrible design for the keyboard really... Any thoughts?

 

Heh, funny aside, I tried running the atari on a 'roku' lcd screen, and I really thought the unit was toast, some carts wouldn't display, sound was there then gone, color was wrong...hooked it up to a panasonic and it displays fine, glad I doublechecked  

Edited December 4, 2020 by High Caliber

[StickJock]

Well, looking at the keyboard matrix, the ESC & TAB are on the same column, and the 1 & Q are on the same column.  Looking at the rows, the ESC & 1 are on the same row and the TAB & Q are on the same row.

 

You didn't mention any other keys out, and since there are more keys on those rows & columns, the lines are good between the keyboard & the controller chips.  Maybe try cleaning the brass contacts on those keys? 

 

If you short the contacts together on the back of the keyboard, do you get the keypresses registered?  If so, then everything is good from the back of the key on.  If not, then maybe there is a cracked trace?  You may try reflowing the solder for those keys?

 

[High Caliber]

15 minutes ago, StickJock said:

Well, looking at the keyboard matrix, the ESC & TAB are on the same column, and the 1 & Q are on the same column.  Looking at the rows, the ESC & 1 are on the same row and the TAB & Q are on the same row.

 

You didn't mention any other keys out, and since there are more keys on those rows & columns, the lines are good between the keyboard & the controller chips.  Maybe try cleaning the brass contacts on those keys? 

 

If you short the contacts together on the back of the keyboard, do you get the keypresses registered?  If so, then everything is good from the back of the key on.  If not, then maybe there is a cracked trace?  You may try reflowing the solder for those keys?

 

Manually touching the contacts doesn't work, and those are the only ones not working.  I'll pop it apart and check for cold solder or a cracked trace...

[RCA1802]

I have had a few 800s that have been sitting for years and I had to work a few keys quite a bit to get the contacts to start working again. 

[High Caliber]

4 hours ago, RCA1802 said:

I have had a few 800s that have been sitting for years and I had to work a few keys quite a bit to get the contacts to start working again. 

I'll be darned.  I got into something else so hadn't taken the 800 apart yet, and I was skeptical about the working the keys....but damn if it hasn't worked on all but the Q key, which I'll look into more tomorrow.  Do you happen to know how common the keyboards with the yellow cup things were?  Really unique design.  I'll hit all the contacts with contact cleaner on q-tips tomorrow, although they looked really shiny.  Thanks for the tip, I was really scratching my head as I know how thick the traces and solder points are on this thing (desoldering a couple of the capacitors was brutal, the traces acted like heat sinks).

 

I always get nostalgic for the ole 800 around Christmas, so really appreciate the help guys, good ole atariage to the rescue.  Cheers and I'll tip back a scotch to you all tomorrow!!  :)))))) 

[Sugarland]

The yellow plungers are failing the worst of all the 800 keyboard variants. The four corners are cracking and not holding the keycaps. The white plungers are also failing but seem to hold the keycaps better. Glad you got most of them working now.  They are called 'wings', the metal contacts under the keycaps.

[TGB1718]

Just for information, although not the cause of this problem, on my 800 after putting an Incognito in

I had keyboard problems and that turned out to be the ribbon cable where it connects to the circuit board.

 

The copper that was exposed had corroded as the 800 had been in a garage for many years and some wires

had cracked when moved.

[mimo]

1 hour ago, TGB1718 said:

Just for information, although not the cause of this problem, on my 800 after putting an Incognito in

I had keyboard problems and that turned out to be the ribbon cable where it connects to the circuit board.

 

The copper that was exposed had corroded as the 800 had been in a garage for many years and some wires

had cracked when moved.

I had a NOS keyboard that when I fitted it nearly all of the connections broke where they were soldered to the keyboard PCB, maybe a common issue?

[High Caliber]

8 hours ago, Sugarland said:

The yellow plungers are failing the worst of all the 800 keyboard variants. The four corners are cracking and not holding the keycaps. The white plungers are also failing but seem to hold the keycaps better. Glad you got most of them working now.  They are called 'wings', the metal contacts under the keycaps.

I actually fused them back together, using a mix of superglue, a soldering iron and yellow 3d print filament.  It was tough, because it needs clearance on both sides of the plastic.  I had hoped to disassemble it and make a mold for replacements, but the thing is soldered and screwed down, it wouldn't be worth it.  So I went with the glue-n-melt method (which was a crazy time consuming task to get right).  Seems to have worked, but I think I might see about sourcing some spares (that aren't of the yellow type).  I'd hate to be in my 80's and not be able to fire up some Jaggi lines  

[High Caliber]

4 hours ago, TGB1718 said:

Just for information, although not the cause of this problem, on my 800 after putting an Incognito in

I had keyboard problems and that turned out to be the ribbon cable where it connects to the circuit board.

 

The copper that was exposed had corroded as the 800 had been in a garage for many years and some wires

had cracked when moved.

Mine is a rainbow color, and actually was in really good shape.  It was half-assed glued down with double sided tape (which is still pliable and sticky!), and the cable was still flexible, and the connector was in great shape.  Now of course, this compy has been kept inside, not in the attic or basement, and nowhere near any UV light, so maybe environment is an issue in the degradation? 

[TGB1718]

5 minutes ago, High Caliber said:

so maybe environment is an issue in the degradation?

Tends to be the killer, unfortunately no matter how much we love them, they do take space and 

consigning them to unsavory places can't be helped sometimes.

 

Even now, I still have my ST's in the garage, but luckily it's a nice modern one with no damp

and I've set them up on some old tables and power them up on a regular basis. 

[High Caliber]

2 hours ago, TGB1718 said:

Tends to be the killer, unfortunately no matter how much we love them, they do take space and 

consigning them to unsavory places can't be helped sometimes.

 

Even now, I still have my ST's in the garage, but luckily it's a nice modern one with no damp

and I've set them up on some old tables and power them up on a regular basis. 

Heh, I hear you, I have a few 2600's in various cupboards around the house...my garage gets to be -20 in winter, and 110 in summer, so I don't even like keeping vehicles out there  

 

Always wanted to play with an ST, but as you say, everything takes up space.