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600/800XL Keyboard variants


Beetle

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Hi all,

 

I have an issue with an Alps keyboard with keys 7,6,U,Y,N being non responsive. Looking at the keyboard matrix this indicates an issue to pin 10, however after following the traces to pin ten, all the points appear to have continuity to both the pcb and the end of the cable so I'm unsure where the issue is.

 

I've attached a photo tracing to pin 10 in yellow. (I had to split the image between two parts as I didn't have a complete photo of the PCB to hand with the cable out of the way).

 

Any assistance appreciated :)

 

 

keyboard matrix.png

Alps pcb trace.png

Alps pcb trace2.png

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Keep checking continuity the whole way to the shoulder of the 4051 pin.  Well, check from the 4051 to the keyboard trace.  If there is no continuity here, figure out where it breaks.  Most likely will be the motherboard to keyboard connector, or the 4051 to it's socket (if it is socketed).  If it is socketed, you could also try removing the chip & putting it back in, which will help break up any insulating corrosion that may be present on the pin/socket interface.  You could also try cleaning the keyboard socket (I used a piece of thin card stock cut to size, like an index card, and stuck in in & out of the connector - amazing how much gunk came out on the card).

 

If you do have continuity all the way from the 4051 to the keyboard, then it may be that your 4051 has gone out.  If they are socketed, try swapping the two 4051 chips.  If the problem keys move, then you have found the problem, and you need to replace the bad 4051 chip.  If the problem does not move with the chips, and you have continuity all the way to the keyboard (well, all the way to the last key on the trace), then, uh, hmm, uh, I don't know.

 

Good luck!

 

Edited by StickJock
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Thanks very much for the reply, sorry I forgot to mention in the post that the keyboard was tested in two different 800XL boards so it looks to be an issue with the keyboard itself. I was expecting to to find a lack of continuity somewhere with a damaged trace and run a jumper wire but all seemed to check out along those traces to pin 10. Perhaps one of the other switch pins within that group of five keys is causing the issue?

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normally if a key is stuck, it will repeat on the screen, perhaps aero dusting could help if a key is resistive but not all the way open or closed...

the other thing would be intermittent cable that work in one position and not another.

take actual resistance reading and not continuity and you can do the same while the keyboard is moved in and out of position... the same thing goes for the keyboard connector on the mother board

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okay, I got to a screen I can see with, you may have cut traces to the right of you middle yellow line near the bottom jumper ...

they could all be short in one way and open in another confusing decode... make sure those traces are completely isolated from each other and restored

you have a number of empty solder pads.. make sure they are properly populated and soldered in... where they are not to be populated they normally can still be filled in with solder making sure any via is solid and stable

 

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Thanks @_The Doctor__ the photos I used in the post were just to illustrate the tracks to pin 10 of the PCB, they were taken from the previous repair I did a few years ago which I had to hand to draw over. There were some trace repairs on this current PCB however and as mentioned all the points going to pin 10 were showing continuity on the meter so I thought this morning that it must be that the trace repairs were perhaps too weak for the lower current from the keyboard connector so I ran a jumper wire from a pin where all the offending keys connect to that part of the matrix and then another directly to pin 10 and all keys are now working flawlessly. It goes to show not to rely too much on my basic meter when diagnosing. Thanks also to @StickJock for your earlier reply.

Edited by Tezz
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On 4/15/2011 at 2:10 AM, Faicuai said:

Thanks for such nice summary!

 

This progression is exactly what I was looking for, since I just finished restoring/upgrading my only 800XL, originally bought in 1984, for which I still have an intact purchase receipt/invoice... :cool:

 

My 800xl is also fully socketed... (I believe that even resistors and capacitors are also socketed on this thing! :) ) I don't recall seeing so many sockets, except on my "Jay Miner" 800.

 

My keyboard is Type 1, without a doubt.

Wow... Never seen socketed resistors and capacitors on an A8 board before. Care to post an image? ?

Edited by Beeblebrox
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4 hours ago, Beeblebrox said:

Never seen socketed resistors and capacitors

And you never will !! ?

 

Just a way of saying the extent to which the MoBo (RevC, Hong-Kong) was socketed, literally everywhere you could see (every single active component).

 

Of course passives are not! ?

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28 minutes ago, Faicuai said:

And you never will !! ?

 

Just a way of saying the extent to which the MoBo (RevC, Hong-Kong) was socketed, literally everywhere you could see (every single active component).

 

Of course passives are not! ?

Ahhh, heh heh, that'll teach me to read it on my mobile. Re-read it just now and realised. ?

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On 4/28/2021 at 5:18 PM, bfollowell said:

I have several 8-bit floating around at the moment. My original 800XL from college that replaced my broken 800, that sadly went out in the trash decades ago. I wish that weren't the case, but that stupidity of youth and all that. My original 800XL bit the bullet last year and I've been trying to troubleshoot it without a lot of luck. Last fall I bought a couple of nasty looking 8-bits, another 800XL and a 600XL for a couple of reasons. One, I thought they'd be fun restoration projects. Two, I thought that, at least the 800XL, would be a good comparison machine to have on the bench while I troubleshoot my original, to compare voltage levels, waveforms, etc. Anyway, both of these have Type 4 mylar keyboards. After reading through this thread, I started pining away for one of those 8-bits with a really nice mechanical keyboard. So, here's the funny part. Today I was tinkering out at my work bench and going through my parts when I pulled out the keyboard for my original 800XL and realized that it has a Type 1 Alps keyboard! I've had one all along and didn't even realize it! I really need to get that machine going again.

 

Now, for a question about my Type 1 Alps keyboard. On the back, lower right of the PCB, it says 600XLKB. This definitely came from an original from the box, never modified 800XL, not a 600XL. Is this common? Do they all say that?

 

 

Congrats on finding it! Yes I think all of the Alps PCB's say 600XLB including the ones for the 800XL's.

 

Presumably this is because the 600XL was considered by Atari the primary machine during development and the 800XL was relegated as a 64K variant. Consequently, initial orders and specs likely went out from Atari as a 600XL keyboard.  Guessing.  Ironically the Alps is very rare on the 600XL's from what I've gathered on ebay over the past six years.

 

Edited by Sugarland
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  • 1 month later...

Wasn't sure if this should go here or into the "Need info on this Atari 800XL system" thread. I recently grabbed a 600XL of of eBay. I  sorted the  search by recently listed to maybe find a quick bargain and jumped on this one when I saw the keyboard. It's the same one from the above mentioned thread and is not listed here among the variants. It looks sort of like a type 4, has that solid feel and level function keys but with different keys caps. They keys are very smooth (they looks nice) and if you notice the slash under the question mark is different. Not sure if it's just because of a different key cap but it makes a totally different sound then my regular type 4 800XL when you type on it. To me it feels different/better to type on. The machine is very clean, no yellowing but only shows a blue screen when it's turned on.  Gonna search the board about the causes of that. Will post pics of the inside when I open her up if anyone wants to look for something that might be different inside.

P1820844.JPG

P1820854.JPG

P1820852.JPG

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@gobo

Beautiful 600XL there. 

 

I've been working on restoring one this week which had various issues and had a brown screen. 

I've managed to restore it and while still sorting issues it now boots up and displays the ready prompt, has sound, and is 95% there. ?

I am working on it some more this weekend and will be posting at some stage a topic thread outlining how I did it, etc. May or May not help. 

 

The one great thing as others may have already mentioned is that the 600XL is socketed so it's very easy to swap out the ICs. 

 

To start with open her up, and gently prise each chip up alternating each side, being careful not to scratch the pcb or bend/break any of the legs/pins. Check for oxidisation on legs/pins and reseat them in their sockets, making sure they are properly back in their sockets. I'd personally test to see if you have any changes after you lift and reseat each chip rather than do them all at once. Takes time but also because they are socketed and this isn't a technical process it's one of the easiest things you can do initially. 

 

Atari used cheap sockets and couple this with the 40 odd years the contact between the legs and sockets can sometimes weaken. Lifting them helps sometimes. 

 

Also you can leave the machine running for a while with lid off, keyboard detached and feel the top of the ICs to see if any of the chips stand out as being very hot. The Ram chips in particular, but also any of the larger 40pin Ics. It's a good indicator of bad ICs. 

 

A lot of the smaller ICs including the ram chips are dirt cheap on Ebay. 

 

There is a wealth of info, expertise and willing/helpful forum members so you are definitely in the right place. 

I'll post an annotated pic of the 600XL in a second when I boot up my laptop. (Currently doing this on my mobile phone). 

 

One other thing, the 600XL has a lot of metal sheilding inside. It can seem daunting removing it. I'll post a link to an existing thread showing you how to release it from the lower casing as there is a small screw which isn't obvious. Also the pcb is very tight in the casing anyway. 

 

Incidentally I don't want to hijack this thread given it's about keyboards so you may want to just start a new thread topic and repost the details, image. Just a suggestion. 

 

EDIT:

 

Ok at my laptop now -  see here for the field service manual and here for the part annotated PCB image:

 

image.thumb.png.a5edff8212465b5d18905c04562b1d02.png

 

Page 59 of the service manual PDF has a troubleshooting section which says this:

 

image.thumb.png.294233c4a8e5aebcdf5b04bbbb6a63a4.png

PDF pages 69-70 gives you the silkscreen (blueprint as it were), which will tell you which IC's are U1-2, and U4.

 

Usually I've found it's never clear cut and your machine may have multiple issues, but it's useful to know. 

 

Finally here is the screw that you'll need to release before the PCB will come out of the casing. (You can't remove the shielding at all unless you remove the entire assembly from the lower plastic casing as there are small nuts and bolts you need to access:

 

I'm still looking for the image of the hidden shielding/pcb release screw. 

 

 

 

 

Edited by Beeblebrox
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I have a 600XL, an 800XL and a 1200XL, and ended up being very fortunate that all three of them were fully socketed, and on top of that the 600XL(AWC) and 800XL(Alps) both had mechanical keyboards. Not a hint of trouble with any of them, and only had one bad key.. and it was just a cracked solder joint. Atari built them good enough. The 1200XL of course needed a keyboard matrix refresh.

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19 minutes ago, rmzalbar said:

I have a 600XL, an 800XL and a 1200XL, and ended up being very fortunate that all three of them were fully socketed, and on top of that the 600XL(AWC) and 800XL(Alps) both had mechanical keyboards. Not a hint of trouble with any of them, and only had one bad key.. and it was just a cracked solder joint. Atari built them good enough. The 1200XL of course needed a keyboard matrix refresh.

@rmzalbar  Nice. Yeah general rule of thumb (AFAIK) is all 600XLs are socketed and any XL machines made in Hong Kong are socketed. Most Taiwan assembled 800XLs are not socketed.  

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@gobo

 

Ahhh, topic post timed out so I couldn't edit it anymore.

 

Here is the extra bit I promised:

 

Finally the video and still from said video below highlights the hidden screw that you'll need to release before the PCB will come out of the casing. (You can't remove the shielding at all unless you remove the entire assembly from the lower plastic casing as there are small nuts and bolts you need to access:

 

Watch this video 2.14min in you see this:

image.thumb.png.33e77398971379ba686cc6cd8eb98e3e.png

 

NOTE: the two holes to the right "are not screws" they relate to the RF module's frequency adjustment (or something related to this). So avoid jamming a screwdriver in these.:grin:

Edited by Beeblebrox
adding more info
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Wow! Thanks Beeblebrox for so much help! I'm planning to hopefully open it up this weekend and see whats up or if there are any surprises inside. I'll start another thread, independent of the keyboard variant in it, on the repair process if it's needed. And again, the help is much appreciated! :)

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1 hour ago, gobo said:

Wow! Thanks Beeblebrox for so much help! I'm planning to hopefully open it up this weekend and see whats up or if there are any surprises inside. I'll start another thread, independent of the keyboard variant in it, on the repair process if it's needed. And again, the help is much appreciated! :)

@gobo

 

Ya welcome. :D  

Edited by Beeblebrox
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18 hours ago, gobo said:

It looks sort of like a type 4, has that solid feel and level function keys but with different keys caps. They keys are very smooth (they looks nice) and if you notice the slash under the question mark is different.

It looks like the SAME keyboard found in a Chelco 800XL "Working Sample" model recently posted here in AtariAge.

 

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2 hours ago, manterola said:

It looks like the SAME keyboard found in a Chelco 800XL "Working Sample" model recently posted here in AtariAge.

 

I think it is. Has the same slash key. The keys have a very smooth ivory like feel to them. Wonder why there seems to be so few of them.

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  • 2 weeks later...

Hi @gobo, I guess you just discovered a new keyboard variant, or at least a new keycap variant.

I also getting a 600XL with this "Type IV + smooth keycaps + weird /" keyboard today. I will open the case and check the inside (under the keycaps).

Mine it is Taiwanese, so that is interesting too. Let's see. The sad part is that it isn't in great shape, it is very yellow, or beige, but I will work on it to make it look decent.

More info to come...

 

 

Edited by manterola
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  • 2 weeks later...
32 minutes ago, yenzee said:

Hi everybody!

Again I have some trouble with an AWC Keyboard in my 600XL. Are there any sources where I can get tha ribbon cable (see picture)?

Greetings from germany,

Jens.

20211031_080854.jpg

You can consider desoldering it completly at both ends (including the socket at the adapter) and using a standard disk-like ribbon cable instead. It should be pretty easy fir this particular type of keyboard. Especially when you have that 600XL adapter. 

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  • 2 weeks later...

What is the best way to clean a type 1 ALPS keyboard? I need to make some repairs to mine. I have all the key caps removed and I'll be replacing the ribbon cable with some new connectors and a different type of cable, but I'd like to clean the board first. This is from my original 800XL and it has been in storage for quite a while and it is filthy. In all honesty, it was probably pretty filthy even before it went into storage. Regardless, I'd like to get it super clean before the repair and restoration. I've heard of some users just putting a keyboard in the dishwasher and running it through a cycle and getting great results. It seems like this is usually with membrane style keyboards. I've used this technique on cases, but I'm somewhat reluctant to try it with a mechanical keyboard with switches soldered to it.

 

I typically use a toothbrush and IA for cleaning PCBs, but it's the other side of the board that needs the most cleaning and I really don't have any decent brushes small enough to fit between the key switches.

 

Any suggestions?

 

Thanks.

 

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