Most liked posts in thread: My 800's keyboard is dead

Luckily I found a guide on AtariAge where a member had the same issue as me, so I can use his tips and guidance in my repairs.

https://atariage.com/forums/topic/222842-my-atari-800-keyboard-repair/?tab=comments#comment-2942105

 

The Hi-Tec keyboard says just that on the bottom side of it. There are 3, IIRC, versions or brands of the Atari 800 keyboards. The earliest models, like the one you gave me, is a Hi-tec (I mistakenly added and H to the spelling before) is mechanical. which means inside the key are two brushes that come together when a key is pressed completing the circuit. They have square white plungers under the key caps which are spring loaded.

StackPole keyboards were the second version, which are also mechanical and very similar to the Hi-Tec in operation, but the plungers are yellow instead of white, and this is the worst version of 800 keyboards as they are the most prone to having the corners of the plungers crack, so the keys are loose and don't work right.

The third type, and final, but also most rare, are the Mitsumi keyboards that are like 1200XL keyboards with a mylar sheet in between the keys and the circuit board, and use rubber plungers instead of springs. These are actually the best 800 keyboards, just like 1200XL's are the best keyboards among XL/XE machines. I think they say Mitsumi on the bottom of the keyboard, but also on the inner mylar I have pictured here.

This is the top of a Hi-tec showing the white plungers. The Stackpole brand, which I could not find an image of, look identical, but have yellow plungers.


Here is the inside of a key, showing the copper metal brushes. Stackpole keyboards are similar.



This is what the bottom of a Hi-Tec keyboard looks like, though this one has been repaired with those jumper wires; the original jumper wires are inaccessible under the keyboard, so this is the way one would have to repair it (like me probably). Mine doesn't even have the screws on the bottom like this one though, but apparently this person could not open his either, so he made repairs to the bottom of the circuit board instead, like I will have too.



This is what a Stackpole brand keyboard looks like on the bottom.




This is what the INSIDE of a Mitsumi keyboard looks like, with it's mylar.


B&C Computervisions (MyAtari on Ebay) ONLY have the worst, Stackpole brand left for sale, and they want $100. Not worth it at all, especially considering they are easily broken. So I guess I'll have to attempt repairs to my Hi-Tec brand.



Now about solder points...basically the solder breaks and separates the component (in this case a keyboard key) from the motherboard so they do not make contact, or poor contact with the board they were once securely soldered too. I found a picture of such an example on-line, since I already "fixed" the ones on my keyboard. The second picture is of various good and bad solder points.

 

That soldering is a tad worrying...I didn't know Stevie Wonder did Atari repairs...

 

Relax Matt, take your time, there's no race here..

Slow but sure..May all your machines shine brightly in the sun...I'm a terrible "get it fixed now" person despite having zero get up and go in me, I've had to understand that "it's done when its done" and it's a hard pill to swallow

I'm so used to doing things at 101% I forget that my body especially my head and eyes can't quite keep up..It leads to annoyance...

Your kit will be back and flying...Good luck my friend...

 

I appreciate the sentiment, but I'm hardly racing with these machines, just on the off day I get a chance to do something or test something with them. I haven't had my 1200XL running for at least a year now, and it's been a couple months for the 800. Though since it is just the keyboard with the 800, I am still able to enjoy a number of games that only need a controller or the function keys to use. So I don't have to resort to an emulator (which I really wouldn't, so for me that means no Atari).

As a programmer loves to program, I love to work on hardware, but neither likes doing debugging and being stuck on the same bug, round and round. The joy is in the creation and moving forward mostly, some in the ability to maintain for yourself, but that gets old if it's always trouble shooting and maintaining. Especially when it's a new issue that crops up when you are trying to upgrade, those are the worst of all. But even if I end up having to change out a dozen resistors and capacitors in the keyboard circuit, I'll get there eventually.

The circumstances point to a mishap in the upgrade work though, and so it's more likely a short or open circuit near one of the 4050's where it doesn't have to be across a dozen circuit traces which is highly unlikely. The more circuits that go out at once, the more likely it's at a bottleneck than across them all.

The truth is, I haven't put more than a total of an hour or two of actual hands on trouble-shooting over the weeks I've had the problem, I haven't even exhausted all the possible testing yet, like continuity across all the keys. I've started with the easiest and most obvious, which is swapping chips and visually following traces and resoldering questionable points. And searching for answers on-line.

My first issue was with the power board that I half-rebuilt, and once I at least got the Incognito SDX and/or memopad screens up, that's when I discovered the keyboard didn't work anymore (for sure-it could have been a lack of partial power from the PSU board).

I know what could happen when I start these projects, as we all do, even if you are experienced and do a mod or upgrade right, these are old machines and sometime the added stress of these projects is just to much for a component or chip, or board. My upgrades and mods over the past few years, in the end, turned out to be done right the first time, after checking over them a dozen times, and it's always been something else, not necessarily even directly related, that has cropped up troubles for me, generally something really stupid I did myself.

With the 1200XL PBI upgrade, I had one connection wrong that was something that had been revised by the project designer, but before I found that out I had swapped out several support IC's including the MMU, and it turned out that I swapped in a bad MMU, but didn't check it again until I had gone over every other possible thing! And that's one hell of a project to go over dozens and dozens of connections dozens of times!

 

Nice time on he shipping! I wish my Turbo Freezer 2011 coming from Greece would have arrived as fast! It was sent out the 28th, and tracking for it stopped when it left Greece the same day...I'm still waiting...

Anyway, I did manage to test out the keyboard with my new 800 board, and it works. So I went ahead and modded the keyboard's ribbon cable with a female connector I had on hand, so it is now ready to properly plug into the male connector on the new mobo. I also made it about half way through the Incognito transfer before I called it a night. I will finish that up today, and then start (hopefully finish) the Pokeymax install today also, which will include a small board to mount the mini-amp & audio video out, which will include either L/R RCA jacks -or- I may go with a stereo headphone out jack like I did on my 1200XL, I'm not sure yet. This board will also include S-video out and composite video out and original mono audio out RCA jack too. And while I'm in there, I may go ahead and add a second SIO port, which may or may not be included on the audio/video out board or on a board of it's own. I haven't decided exactly where I will mount them on the case yet.

Another plan of mine that may change a bit (have to wait on the Turbo Freezer to arrive) is my planned PBI port which originally I was going to make an adapter for the 800's hidden rear edge connector. But since the Turbo Freezer has a pass-thru PBI card edge on it, I am now contemplating the idea, if I can find a good spot in the case, to install it internally, connected directly to the Incognito's PBI lines and then mount the Turbo Freezer where the pass-thru PBI can be accessed on the exterior.

Again, this idea depends if I can find a good place to mount it. It will probably be mounted so it's accessed in the rear like the XL/XE's, but it may have to be mounted higher up so that any other PBI devices plugged in will have to have little legs underneath to support it, and off to the rear left side or the other of case, since there's not much room to mount anything between the shielding and the case in the rear or the other side where the PSU board is located.

I've also go additional controller ports (for the second PIA) to think about mounting too, but I think they will be hidden under one of the 800's rear sides that are recessed. Which will mean lifting up the machine to plug stuff into the ports, but it will still, at least, be easier to access than the Atari ST's under-the-keyboard mouse & controller ports!

This is all tenuous atm, while I decide what it best..I'm already second guessing audio/video out the rear, I may stash the output board under the PSU board in the front and mount the jacks underneath coming out the recessed area on one side and the new controller ports in the opposite recessed area.

It seems like I'm forgetting some mod/upgrades I'd planned, but I can't seem to recall them atm...anyway, I should be writing these ideas up in my hardware upgrade blog instead of this keyboard repair thread...this should be my last post in this thread. Look for further updates in my blog, as well as pictures of my keyboard ribbon cable mod and Pokeymax, etc. installation.

 

Yeah...not so much (working). My old motherboard worked in as much as Incognito boot-strapping once I converted from stock back to it after getting the "Red/Yellow/Green* screen of death the last time I assemble it a few months ago. The keyboard did not work still. Then I plugged the keyboard and the stock CPU/OS/RAM into the new motherboard and it boot-strapped to memopad and the keyboard worked. Then I finished transplanting the Incognito to the new motherboard today, and all I get is Red screen. Which generally has to do with a problem with the CPU board, OS board or ram.

I quintuple checked my installation of the Incognito all day today with no success. I'm about to remove it and revert back to stock, leaving the CPU card in, to identify or eliminate the Incognito itself as the culprit, if I still get a red screen with stock OS and ram then something went bell-up on the CPU board, which surprises me because it's a NOS board, but I have an extra NTSC and PAL CPU boards that only have pot issues, which I can start swapping out IC's from. I also have extras of pretty much all the IC's from my XL's too. But it's like I've been cursed for the past year or so with constant issues like this.

One moment I'll assemble it and it all works, and I start moving forward (or side-ways), do one small mod or upgrade, and suddenly it doesn't work when I re-assemble it. And chances are, I may merely return it to stock, test it working, re-install the Incognito again and it will suddenly work. At least that's what I'm hoping since it's already happened more than once trouble-shooting this 800. But this was a virgin motherboard that tested good stock yesterday. But I also know, NOS or used, it's all old and any component could give out without warning at any time. At least I started using Dupont connectors which really helps with installation and removal after the first time.

There just isn't much too this Incognito upgrade, 6 wires to or on the motherboard, and one ribbon cable to a socket, and 2 wires to the Antic on the CPU board, and the rest is plug-in. I did a PBI upgrade with well over a hundred connections just a couple years ago and didn't have so many issues for God's sake!

It's utterly frustrating and the reason why I give up for days, weeks, or months at a time.

*Depending on Atari model and if PAL/NTSC

 

Oh Bugger Thought you had it sussed out as well. I've just had the same issues with an Amstrad CPC6128
all seemed to work fine, desoldered OS & DOS ROMs socketed put back together , didn't want to work.
At this point the board is out of it case just with power and Monitor cable in, checked PSU, o.k Checked on plug into board o.k , checked on chips for 5V nothing. hmm checked switch a known problem on these o.k plugged in all worked.
did some other mods, didn't work.checked 5V rail nothing again.. I've just stopped but thingk it's the PCB mounted DC in socket as with PSU plugged in checking directly on socket and no volts on the middle pin... it's 2:30 in the morning here so going to bed and giving up for now. I'll see in the morning..

 

The silver lining to all this is that I have my confidence back that I do know what I'm doing and not making stupid mistakes I'm unaware of when it come to repairs and upgrades, since there is nothing wrong with the old motherboard. And I know I have a working motherboard for my robot project when the time comes to make it mobile. Also that I can trust my own instincts and not to second guess myself just because I can't prove those instincts correct right away, and not start assuming I was wrong and it's something else. This all encourages me to keep trying to move forward with these projects.

 

If it requires a PS/2 keyboard I don't have one right now, only USB, unless you can use an adapter, but then I'd have to get one of those too. Is there more to it than shown? I see a bunch of menacing pins that need to be hooked up to something...I have been hard at work all day and I'm too tired to care atm, anyway. We can just wait until you are back to see about this, but thanks...off to go rest now...

 

Hi Matt
Yep intime just going to the Post Office now.

 

Stackpole is the same type as the Oric Atmos keyboard and the contacts cause connection problems later on as the little leaf springs inside stop making contact. Irrelevant to fixing an 800 keyboard I know but another reason to not buy one, unless the high tech ones have the same problem with the similarities in their design but it would be very unusual for all of them to pack in at the same time.
Theoretically it must be either the tracks,links or contacts... have you measured the impedance when you press a key?

 

Not much help but good luck with getting a good fix...Still can't get over that line of solder blobs, a true who's who of how NOT to solder..

 

My thinking all along was it isn't the keyboard, since none of the keys were working (except the BREAK key). This is the Field Service Manual's way of thinking too. All the IC's concerned have been swapped several times with new or known working chips. The computer works, with Incognito installed or reverted too stock (as now), but with the Incognito and no keyboard it goes straight to SDX, you have to have a working keyboard to get to the BIOS menu or even type CAR to run a cartridge, so I have it reverted to stock until I figure it out.

But, there was the nagging issue of "why does the BREAK key work?" The FSM says if some keys work, but not all, it's the keyboard. If all keys don't work, check the Pokey and 4050 IC's which I have. I haven't gotten around to checking continuity yet, but I find it hard to believe that an entire row of resistors or capacitors before the connector would have all gone bad at once, except one. I was about to remove the sockets on the mobo for the 4050 IC's and change them out, and make sure that no rouge solder balls or bits of wire got underneath the sockets and are causing a short.

Maybe the POKEY as well, however, in stock condition I can run cartridges and auto-load disks, and they work fine and the Pokey sounds and music play if I can start the games with either a joystick button or one of the function keys not on the same circuit as the keyboard. So I don't believe the issue is immediately at the POKEY chip. But I will do a continuity check on the keyboard the best I can without an Oscilloscope as the FSM calls for, with my multi-meter next.

 

Isn't the BREAK key hardwired differently to the other keys.....I seem to remember something about that...Will have a dig...

Could only find this

http://krap.pl/mirrorz/atari/homepa.../Atari/800XL/atari_hw/pokey.htm#keyboard scan

 

But I've also been thinking about jumping back on my 1200XL, trouble shooting it to get a break from the 800. The 1200XL is a red screen issue, and the only things I haven't checked are the OS and ram chips (brand new, recently replaced after reverting back to 64K internal and using Syscheck's 512K). So I may go ahead and reverse the 32-in-1 upgrade in my 1200XL, back to the original 1200XL OS, since I do have the Syscheck with 3-4 other OS slots available anyway. And once I get it working that way, I can always burn the 4-in-1 eproms to replace the original OS again later (and get back BASIC or other rom internally too). And I have more 64K and 256K drams on hand, NOS, so if it is a ram issue...

 

If I'm understanding the FSM schematics and flow charts correctly, which I think I am, it is part of the same circuit. It's not considered a function key like the START/SELECT/OPTION and RESET are (also HELP on XL/XE's) which are on a different circuit and controlled by the PIA, IIRC, instead of the POKEY. But I do see what you mean, at the link, it does show BREAK/SHIFT/CONTROL separated from the other keys somehow. And I can't know if SHIFT or CONTROL work without the other keys or I suppose a continuity check.

If that is the case, and looking closer into it, it does look like the BREAK/SHIFT/CONTROL are routed through one 4050 IC and the other keys through the other. Which would follow my theory that a bit of solder or wire got caught under one of the 4050's sockets and is shorting things out. Under inspection without removal, my eyesight, even aided, can't see well enough, but I *think* I saw something...

 

I feel it is the keyboard and something on the PCB from what you described. If there is a problem there it could pull the impedance down to a point that keyboard presses don’t register. If the BREAK key still works and it’s on a separate circuit that might explain the anomaly.
It will get fixed, just need to set some time aside and work through it methodically.

 

!KR2 is directly connected to the POKEY based on that diagram so there is a little difference to the rest of the keys.

 

I'm liking my foreign object under a socket on a 4050 theory more and more, since the solder/resin/brushes/wire and solder iron had all been recently involved. I

also forgot to mention that there is no issue with my keyboard's circuit board like the guy that did the AA thread I link had. I carefully went over it and verified all good solder points, no solder pads pulled or cold solder joints, traces all intact. So it really makes me want to go back to my original theory that it's not the keyboard. It's such a simple on-off circuit with no IC's on the keyboards circuit board. I know all the brushes for the keys are good, even the few I had to bend back in place during repairs. all cleaned and shiny.

 

4050's are dirt cheap and common

 

@Paul "Mclaneinc" Irvine I know, I just bought a pack of 10 of them off Amazon after already trying the 6 I had on hand from other machines.

I was just reading the circuit diagram in the PDF FSM, and I do see that the two 4050's are tied in together, and do not operate with the keyboard in parallel. So if one is out, the other will be too, no half keyboard working if it goes through either of them. And of course what @Vyper68 said, the BREAK key runs directly from the POKEY with the other two keys.

So checking continuity will be the almost next step, right after I lift at least one of the 4050 sockets and make sure there is no short.

 

Wish I could offer more help Matt, you are miles ahead of me in circuit checking, the reference to the BREAK key I made was just one of those little facts you store away and it comes in handy sometimes. As for my knowledge of the 4050's, I seem to remember them to be gate arrays but this is stuff in my head from the 80 and 90's, I'm simply remembering the picture of the catalogue page from Maplin. I used to have a photographic memory but all that went south after my mental health issues, some is still there but to be fair I just sold them or soldered them in to preexisting kits, their actual use is foreign to me

To quote a favourite old phrase I heard once, "I was born with nothing and still have plenty of it left"

Just Googled it and it's from a great source, Mr Groucho Marx himself..

http://www.mactheknife.org/Thoracic/Quotable_Quotes.html

 

I remembered, again, why I hadn't done this before; because the 1200XL OS doesn't support the PBI and then I couldn't use the Syscheck board.