800XL Alps keyboard repair

[Doug_in_NC]

Good evening everyone, this is my first post here, and I’m a brand new 800XL owner, so please forgive me if my grasp of the terminology is lacking. I bought an 800XL on e bay a couple of weeks ago with some upgrades and a 1050 drive. A second “untested” 800XL was thrown in with it. As you would expect, it was DOA. As the keyboard on the “working” one didn’t work, I swapped them over, and confirmed that about 4 keys on the dead one were functional. Now I have a new Mylar for the working system, I am trying to work out what to do with the “untested” one. As so many of the keys and the LED don’t work, I’m guessing that this is probably a connector problem and not a key switch issue (the keyboard says it’s an Alps, which is a mechanical keyboard, right?) Is there an off the shelf connector that would fit the keyboard connector on the main board that I could solder onto a piece of ribbon cable to replace the cable that is there now, assuming I confirm that the connector is the problem?

 

As an aside, the keyboard pcb says it’s a 600xl keyboard, so it may not have originated with my machine. Am I correct in assuming that the 600XL and 800XL keyboards are interchangeable?

[+Nezgar]

For the alps mechanical keys - if they are not working, keep tapping the nonworking keys repeatedly - seriously just keep at it, after 5 minutes of hammering on a key it should start responding. Have the self test keyboard test up if you can get to it with the console keys. (Hold option at poweron)

 

Had a few machines I had to give this treatment. Takes time, but it works! Cleans up years of corrosion from non use on the metal contacts inside the keyswitches.

 

Lastly - welcome to atariage, I only joined about 4 yrs ago as well and it's been a fantastic ride!

[Doug_in_NC]

Thanks! I will check the board with a multimeter and if it confirms the keys are the problem, I will try your fix. This isn’t only one or two keys not working, it’s about 4 that are and the rest not, so banging each one for five minutes is going to take a while! 

[mimo]

I bought an Alps keyboard back to life by removing the key caps, a quick squirt of electrical contact cleaner in each switch and repeatedly pressing each one 100 times or more.

[+Nezgar]

27 minutes ago, Doug_in_NC said:

Thanks! I will check the board with a multimeter and if it confirms the keys are the problem, I will try your fix. This isn’t only one or two keys not working, it’s about 4 that are and the rest not, so banging each one for five minutes is going to take a while! 

Well, if it's any consolation, I had at least one keyboard where 90% of the keys didn't function at first.... It took a while to revive them all haha.

 

Oh and for the DOA 800XL, is it just the keyboard that is non functional, or the whole system? With two 800XL's your troubleshooting options are much easier - start swapping IC's one by one from the non-working system into the working system, and see when you get a fault to narrow down which might be the problem. If you by chance get through them all without a problem found, then there's something else at the component level on the mainboard which will take a bit more effort to find, but let's see what you find and I'm sure the folks here can help you narrow it down!

[Doug_in_NC]

Oh, I have a pretty good idea what is wrong with the main board, or at least some of the problems ? It used to have what I guess was an Ultimate 1 MB board in it, and it was taken out, but the original chips not replaced, so the OS and MMU are missing. Beyond that, someone tried to pull out one of the socketed 74 series logic chips and managed to rip the socket half out of the board, though fortunately the pins stayed in place, so it *probably* didn't damage the board. My next problem is that the working one has an Ultimate 1MB in it too, so I don't have the MMU and OS to swap over, so I have to replace them before I start. Still I guess, once I have replaced that lot, there's a chance the board may work without further work.

 

I checked all the switches and there were a couple that were a bit sticky and needed to be pressed a couple or times, but the others worked fine, so I tried swapping the keyboard into the working machine. and it was a very tight fit. I got it in but couldn't get any response. I put the original one back in, and sure enough it was dead too ? The Alps one has a much thicker connector than the mylar on the Stackpole, and it had pushed all of the metal connections in the board connector so was just way too loose. Took me an hour or so with a needle to bend them all out properly so the Stackpole would work properly again. I think I am going to have to start on resurrecting the board before I work on the keyboard (which fits easily into the connector on the machine it comes with). It looks like at least for me, those different designs of keyboards are not interchangeable. 

Edited December 20, 2020 by Doug_in_NC

[djglish]

I have a dead 800XL that you could have the chips from.  Just need to know which ones they are (not sure of how to find their location on the board.  If they are socketed it will be easy.  You can have them for the cost of shipping. 

 

I took the keyboard connector off of the MB to build a mini PC into the Atari case.

 

I'm located in Wisconsin.

[Doug_in_NC]

That would be great! I will take some photos tomorrow and post them here so you can see what I need. 

[Doug_in_NC]

Here is a picture of the board and closeups of the 2 chips that have been remove (U3 and U5 on my board). I'm not sure if there are no sockets because the previous owner wanted to keep the profile low and so they removed them. or because these weren't socketed in the first place. Ifyours aren't socketed, please don't go to the effort of desoldering them - I can probably get replacements from Best Electronics. I have included a shot of the half pulled out logic chip socket just for interest - I have a replacement chip for that one. If you look closely at the shot of the board, you can see some of the added connections for the 1MB board that have just been cut off and left there.

[djglish]

Just looked and both chips U3 and U5 are socketed.  

If you send me a personal message with your contact info i can send it to you.

 

[hueyjones70]

Where are you in NC?  I am in NC also about 25 miles east of Raleigh. I have repaired dozens of 800XLs and I would be glad to see if I could figure out what exactly is wrong with the DOA. If you are going to get seriously into the Atari community you probably want to fix it yourself. The first step would be to solder sockets into the place where they are missing. Then you insert working chips into the missing spaces. If the computer is still dead, you start swapping chips from the dead one to the working one until you find the culprit.  I could mail you the sockets if you want to become a regular Atari freak/nerd.

[hueyjones70]

Pull a keycap and take a picture of the mechanical switch, I may be able to give you some tips on repair, depending on the type of switch.

[hueyjones70]

I just realized that your location is given in your initial post.

[Doug_in_NC]

I had planned on repairing the board myself. I got the sockets required just before Christmas and will solder them in, and then replace the logic chip socket and the chip. Then I need to get hold of the 2 missing chips, so I guess Best is the best place for them. As I mentioned above, whoever owned it before me had installed and then removed a 1MB board, and not replaced the original OS and MMU. As the working board also has a 1MB board in it (maybe the same one?), I need to get those 2 chips before I can start diagnosing what if anything is wrong elsewhere. I checked the connections for all of the keyboard switches, and at least the switches themselves all function. 

[Ppyo]

Hey Doug_in_NC !

I am your almost neighbor in Rock Hill, and I also got an 800XL from Ebay. The keyboard is also broken (Is that a trend with the XLs?), because only the Reset, Option, Select, Start, and Break keys work. I'd like to know if it is the actual keyboard assembly I need to replace (the mylar replacement), or if it is the Pokey chip.

I am also considering getting the Ultimate 1MB upgrade, so I am curious to see it IRL...

 

[Ppyo]

Welp, after a nice, in depth cleaning prepping the XL for Ultimate 1Mb installation, keyboard is working great again!

Also, the memory upgrade went well. Ultimate 1Mb is a must have upgrade! Now thinking of upgrading to the UAV to improve video quality.