Atari 1200xl Keyboard Repairs

[Jeffrey Worley]

Since my return from the dead all I've been hearing about the 1200xl keyboard (and the mitsumi 800 keyboard) is that they are failures.  I have decades of experience with these machines and I deny that these keyboards are anything but excellent.

 

This keyboard design likes to be used.  If you don't use it, two things will happen:

 

1)  The mylar, over years, will become ever so slightly stiffer.  You would need a special gauge to test this but it is so.  I know.

 

2)  The springs under the silicon rubber contactors - these springs actually provide the pressing force on the mylar - will collapse ever so little, reducing the effort they can exert on the mylar.

 

To fix this fault:

 

Take the 30 odd screws out of the bottom of the keyboard.  It will separate cleanly into two sections, the key part and the pcb.  No parts will be loose to worry about.

 

Remove the PCB and examine the mylar.  Sweep your hand over the top of the mylar, working it a little, flexing it a little, without peeling it or otherwise attempting to remove it.  You are only saying hello, wake up.

 

Install the naked PCB into the keyboard connector on your 1200xl and at a prompt of some sort, or the keyboard test, or whatever, test each of the keys by pressing on the contact pad.  You will find there is nothing at all wrong with the mylar.  Very light touch, no hesitation.

 

Now, to rejuvenate the keyboard you will need exercise some judgement.  Each spring under each silicone rubber contacto needs to be streached, A MILLIMETER OR TWO.   The metric here is that once the spring is reinstalled, if you hold the keyboard at eye-level aso that all keys are facing down and suspended in the air (at rest), scanning the contactors in thier little holes, no contactor extends even a hairs breadth above the top of the plastic channel it travels in.  You want to reduce the travel distance to the mylar to basically zero without putting any actual pressure on the mylar -saving this for a keypress!

 

Once you have treated all springs and have assured yourself they are all of the correct dimensions, put the PCB back on the board and check for any pressure back at you.  The PCB should fit snugly with no feel of any pressure against it.

 

Install a cross of screws to secure the PCB for the moment, install the keyboard and test it. If you have function in all the keys, reassemble and test.

 

If your keyboard does not work at all, you have one or more keys pressing on the mylar at the rest state and you will need to eyeball the level of the contactors again.

 

There are two ways you can adjust the contactors:  1)  you can remove the spring and give it a good squish before reinstalling and eyeballing the results.

 

If once you install all the screws you have a non-working keyboard, go through all the screws and untighten them 1/4 to 1/2 turn.  Test again.  Bet you have function.  Now seat the screws without overtightening them.

 

OK, So no you have a perfect keyboard, but it is stiff, gripey.  To renew your keyboard's feel and travel:

 

1)  remove all screws from the bottom of the keyboard.  Remove the pcb and carefully set it aside.

 

2)  Examine each key from the bottom.  You will see that it slides in two plastic guides.  Orient the keyboard so that it is suspended in the air, upside-down, spacebar to your right.

 

3)  While maintaining the orientation in step 2, using a precision oiler (syringe with metal tip) filled with white lithium grease, carefully place a dot of grease in each track you see at the joint where the key and track meet.  The next time you operate this key, the dot will spread to the entire track.  Once you have done all the high-side tracks you are half done.  Flip the board so that the spacebar is to your right and do the other track for each key.

 

4)  Place the keyboard on a flat clean surface and operate every key two or three times to distribute the lubrication.

 

5) Reassemble the keyboard with a cross of screws and test.  If all keys are basically functional, reassemble the keyboard without overtorquing the screws.  You can go back and tighten the screws at leisure.

 

6)  Operation is likely to be flaky.  Please operate each iffy key several times until its iffiness goes away.  Often this is the only thing needed for a patient person to restore a 1200xl keyboard.

 

Basically, this keyboard design likes attention.  If it doesn't get attention, it sulks, feels it is owed some back attention.  Thus, you need to repay the keystrokes the keyboard feels it has been shorted.  Once you have paid the balance of keystrokes the keyboard will work flawlessly from then on.  In the 80's and 90's this was the only thing needed, but the extra decades in storage have made the job more involved but still just a wake-up, no parts needed.

 

If you have keys that stick after reassembly, you may be able to just back off of the screw or screws nearest that key until things settle down.  Use will bed everything in and you can then reseat your screws fully.

 

Best regards,

 

Jeff

 

 

[+bob1200xl]

Uuummmm... (oh, my goodness)

 

I don't want to start anything here but my experience with 1200XL keyboards is somewhat different than yours. The point of failure is the interconnection between the mylar and the PCB. The mylar contacts lose continuity and need to be re-coated or replaced. You sound like you have a third option. (nice writeup)

 

Best Electronics makes a replacement mylar that works very well. Pull off the old mylar, clean the PCB with GOOF-OFF or alcohol (90% +), and position the new mylar. Six zillion little screws later and you're good to go.

 

Even the new mylar may resist making good contact, so you may have to re-position it a little. Don't bother with that little interposer board. Works perfect without it once you get happy.

 

Or, you can just touch up the original mylar. Instructions are around here somewhere...

 

Bob

[+bob1200xl]

Hey... Don't I know you?

 

Welcome back!

 

Bob

 

[Jeffrey Worley]

5 minutes ago, bob1200xl said:

Hey... Don't I know you?

 

Welcome back!

 

Bob

 

Thanks man.  Is this Bob Wooley?

[Jeffrey Worley]

39 minutes ago, bob1200xl said:

Uuummmm... (oh, my goodness)

 

I don't want to start anything here but my experience with 1200XL keyboards is somewhat different than yours. The point of failure is the interconnection between the mylar and the PCB. The mylar contacts lose continuity and need to be re-coated or replaced. You sound like you have a third option. (nice writeup)

 

Best Electronics makes a replacement mylar that works very well. Pull off the old mylar, clean the PCB with GOOF-OFF or alcohol (90% +), and position the new mylar. Six zillion little screws later and you're good to go.

 

Even the new mylar may resist making good contact, so you may have to re-position it a little. Don't bother with that little interposer board. Works perfect without it once you get happy.

 

Or, you can just touch up the original mylar. Instructions are around here somewhere...

 

Bob

The mylar is tough to pick up from my recollection, the points where the screw holes pinch the mylar and pcb together so the become bonded.  Shimming it off is possible, but having a replacement mylar handy is a plus 'cause it's pretty iffy if you can re-use this one.

 

Operating the switches on the naked PCB a buncha times can really help too.

 

Jeff

[+DrVenkman]

47 minutes ago, Jeffrey Worley said:

The mylar is tough to pick up from my recollection, the points where the screw holes pinch the mylar and pcb together so the become bonded.  Shimming it off is possible, but having a replacement mylar handy is a plus 'cause it's pretty iffy if you can re-use this one.

 

Heating the keyboard assembly with a hair dryer at the point you start peeling off works wonders. I have removed and repaired the Mylars on two of my 1200XL's without a problem, other than it being tedious.

 

http://retrobits.net/atari/keyboard.shtml

[Jeffrey Worley]

1 minute ago, DrVenkman said:

Heating the keyboard assembly with a hair dryer at the point you start peeling off works wonders. I have removed and repaired the Mylars on two of my 1200XL's without a problem, other than it being tedious.

 

http://retrobits.net/atari/keyboard.shtml

NIce tip!  I do that to peel off ribbon cables to re-use the connectors.

 

Best,

 

Jeff

[flashjazzcat]

tl;dr version:

 

 

[Jeffrey Worley]

Wow, Flash, you are one dedicated guy.  But there is a thing called a battery.  They combined these with the screwdriver to automate this process some time ago.  Thought you might like to know. 

 

 

[flashjazzcat]

1 hour ago, Jeffrey Worley said:

But there is a thing called a battery.  They combined these with the screwdriver to automate this process some time ago.

I am no fan of using these things on self-tappers in ancient plastic, especially when tightening (when screw must be carefully backed up to find thread and not over-tightened). Quite happy with manual methods, thank you.

[Jeffrey Worley]

1 hour ago, flashjazzcat said:

I am no fan of using these things on self-tappers in ancient plastic, especially when tightening (when screw must be carefully backed up to find thread and not over-tightened). Quite happy with manual methods, thank you.

I use mine and try to be careful, but stripped screws do happen.  I wish I had one that had a slip clutch.  Too expensive.

 

best,

 

Jeff

[+bob1200xl]

19 hours ago, Jeffrey Worley said:

Thanks man.  Is this Bob Wooley?

Huh?  Lemme check....

 

Ya! I'm Bob Woolley!

 

Bob

 

 

[+kheller2]

I'm not following how the first post in this thread contradicts the still having to repair 1200XL keyboards....  yes they are wonderful..  but they deteriorate and have to be repaired.

 

[Jeffrey Worley]

8 minutes ago, kheller2 said:

I'm not following how the first post in this thread contradicts the still having to repair 1200XL keyboards....  yes they are wonderful..  but they deteriorate and have to be repaired.

 

I see your point.  I'm not so much as defending the keyboard as decrying the default of replacing the mylar.  Most of the time it isn't necessary, like 'recapping' perfectly working machines.  I wanted to systemize the fix so the keyboards got the best kind of attention.  Lubricating the keys the way I did really really really helps the feel.  Wow.

 

Jeff

 

[elmer]

On 1/12/2020 at 3:49 PM, bob1200xl said:

Best Electronics makes a replacement mylar that works very well. Pull off the old mylar, clean the PCB with GOOF-OFF or alcohol (90% +), and position the new mylar. Six zillion little screws later and you're good to go.

 

Even the new mylar may resist making good contact, so you may have to re-position it a little. Don't bother with that little interposer board. Works perfect without it once you get happy.

 

Yep, this is what I did (very carefully), and I got lucky and it worked first time.

 

Even the removal of the old mylar was pretty smooth with a heat-gun/hair-dryer.

 

I'm still trying to decide whether the final step is either a UAV, or the ClearPic 2002 mod. ?

[tjlazer]

I have two Atari 1200XL computers and both keyboards did not work anymore.  I thought the mylars were bad.  When Best Electronics released their new ones I bought two.  When I had time to work on these I found that if I hit each key hard many times they started to work!  I then spent a while hitting each key really hard 50 times or so until it started to work. I did this to each key and eventually they all were working!  I still have my mylars incase I need them later, but for now this method worked for me!

[Jeffrey Worley]

3 minutes ago, tjlazer said:

I have two Atari 1200XL computers and both keyboards did not work anymore.  I thought the mylars were bad.  When Best Electronics released their new ones I bought two.  When I had time to work on these I found that if I hit each key hard many times they started to work!  I then spent a while hitting each key really hard 50 times or so until it started to work. I did this to each key and eventually they all were working!  I still have my mylars incase I need them later, but for now this method worked for me!

This is the truth.  Oh, and the design of the keyboard pretty much makes the amount of pressure you use immaterial.  So pressing the keys fully is the same as whacking it really hard.  What DOES help speed things up a lot is to press the key down fully, not with any special pressure, and wiggle the key around.  There's not much play there, but use what there is and the key will stutter and stutter and start to work more and more and eventually wiggling it won't make it stutter any more, only a standard unbroken key repeat.  This is the test of a good key.

 

Best,

 

Jeff

[+mytek]

I buy PS/2 keyboards from thrift stores for around $3-4 on a regular basis. If one of those stops working I toss it and grab another off my pile .

 

Of course that requires something like a TK-II or AKI to enable the use of a PS/2 keyboard in the first place. Speaking of which, I'm working on a new design of the TK-II for use in all of the 400/800, XL, XE systems.

 

 

It'll allow you to use the arrow keys and the Left-Win key as a joystick and trigger for playing games using the keyboard. Nice thing is that it'll look just like a joystick to the hardware, so no mods required to any of the games to have it work. I'm presently testing a version in my XLD. More info will be posted in a separate thread when this is ready for prime time (don't want to derail this thread any more than I have).

 

[+bob1200xl]

mouse, mouse, mouse......

[Jeffrey Worley]

13 minutes ago, bob1200xl said:

mouse, mouse, mouse......

Really.  The big problem with both Atari and Amiga machines are the mice.  I have a Jerry adapter, but even that is pretty limited - it recognizes only a handful of mice having a USB connector but using PS/2 signalling.  I'm hunting for a mouse right now and having iffy luck.  Same with keyboards.  A keyboard for an Amiga would set you back hard.  One for  the Mega ST as well.  It would be good if we has an adapter that would run a standard USB keyboard and mouse, doing the necessary conversions on the fly.  I'd rather have the original keyboard, but for testing and just banging away, a cheap disposable keyboard would be a godsend.

 

jeff

 

Edited January 14, 2020 by Jeffrey Worley

[+mytek]

1 hour ago, bob1200xl said:

mouse, mouse, mouse......

Bob have you developed a stutter? BTW, they make some good traps for those things .

 

1 hour ago, Jeffrey Worley said:

Really.  The big problem with both Atari and Amiga machines are the mice.  I have a Jerry adapter, but even that is pretty limited - it recognizes only a handful of mice having a USB connector but using PS/2 signalling.  I'm hunting for a mouse right now and having iffy luck.

MacRorie has created some PS/2 to Mouse adapters for the A8 or the ST based on my MouseTari chip. The Logitech M-SBF96 works very well with it, and it's an optical mouse so no fussing with cleaning your mouse balls.

 

1 hour ago, Jeffrey Worley said:

I'd rather have the original keyboard, but for testing and just banging away, a cheap disposable keyboard would be a godsend.

Obviously the stock 1200XL keyboard is a great keyboard. I use a TK-II-PB board in my 1200XL as the means to play around inside without having to constantly plug the stock keyboard in to test something.

 

Here's what that looks like, using the RF jack hole for access to the Mini-DIN6 jack.

 

 

The new board I'm working on will be even more compact.

 

 

[Jeffrey Worley]

Does pulling the RF modulator clean up 1200xl video?  I imagine it would have a salutary effect, but how much?

[Jeffrey Worley]

1 hour ago, mytek said:

Bob have you developed a stutter? BTW, they make some good traps for those things .

 

MacRorie has created some PS/2 to Mouse adapters for the A8 or the ST based on my MouseTari chip. The Logitech M-SBF96 works very well with it, and it's an optical mouse so no fussing with cleaning your mouse balls.

 

Obviously the stock 1200XL keyboard is a great keyboard. I use a TK-II-PB board in my 1200XL as the means to play around inside without having to constantly plug the stock keyboard in to test something.

 

Here's what that looks like, using the RF jack hole for access to the Mini-DIN6 jack.

 

 

The new board I'm working on will be even more compact.

 

 

Oh wow.  you built the Transkey!  I bought one of those in 1993 or 94' and never did get it to work.  I know they DID work, but I either got a bad prom or botched the install so badly as to damage the Transkey.  Sigh.

 

Best,

 

jeff

[+mytek]

1 hour ago, Jeffrey Worley said:

Oh wow.  you built the Transkey!  I bought one of those in 1993 or 94' and never did get it to work.  I know they DID work, but I either got a bad prom or botched the install so badly as to damage the Transkey.  Sigh.

Yes I designed and built the original 1990 TransKey, although I wasn't entirely happy with the end product, which in my opinion was still a bit buggy. It was designed with the AT style keyboards of the time, which were close to PS/2 in communication, but sometimes not close enough. It really came down to the luck of the draw with which keyboard you were actually using.

 

The PS/2 standard that followed really cleaned things up, and created a more standard interface.

 

For years I always wanted to go back and revisit this, and then use the new powerful MCU's that now exist. Well I finally got my wish in May of 2015. At first I got off to a rocky start, having to relearn the ways of Pokey all over again, and also getting sidetracked with the notion of providing a mouse controlled arrow aspect which I abandoned many versions ago. Emulating an ST mouse in a separate MCU made a lot more sense. I also had to give up on the idea of having the PS/2 keyboard's Caps Lock indicator reflect the state of the Atari, which there is no certain way to know via Pokey alone. So with the last 2.4 iteration of firmware, things really took on a solid form, and virtually any PS/2 keyboard should work reliably, even as far back as the IBM Model M clicky clack buckling spring version, which is one of my favorites.

 

With this new Pokey piggyback board, there will also be a corresponding release of V2.5J firmware that will take advantage of the new Arrow to Joystick mode, as well as allow for 2 different mappings of the Function keys (Standard TK-II, or DarkAKI).

 

1 hour ago, Jeffrey Worley said:

Does pulling the RF modulator clean up 1200xl video?  I imagine it would have a salutary effect, but how much?

Not really. But it does provide a nice place to put the PS/2 jack without modification of the case other than a slight enlargement of the existing hole.

 

[Jeffrey Worley]

17 hours ago, mytek said:

Yes I designed and built the original 1990 TransKey, although I wasn't entirely happy with the end product, which in my opinion was still a bit buggy. It was designed with the AT style keyboards of the time, which were close to PS/2 in communication, but sometimes not close enough. It really came down to the luck of the draw with which keyboard you were actually using.

 

The PS/2 standard that followed really cleaned things up, and created a more standard interface.

 

For years I always wanted to go back and revisit this, and then use the new powerful MCU's that now exist. Well I finally got my wish in May of 2015. At first I got off to a rocky start, having to relearn the ways of Pokey all over again, and also getting sidetracked with the notion of providing a mouse controlled arrow aspect which I abandoned many versions ago. Emulating an ST mouse in a separate MCU made a lot more sense. I also had to give up on the idea of having the PS/2 keyboard's Caps Lock indicator reflect the state of the Atari, which there is no certain way to know via Pokey alone. So with the last 2.4 iteration of firmware, things really took on a solid form, and virtually any PS/2 keyboard should work reliably, even as far back as the IBM Model M clicky clack buckling spring version, which is one of my favorites.

 

With this new Pokey piggyback board, there will also be a corresponding release of V2.5J firmware that will take advantage of the new Arrow to Joystick mode, as well as allow for 2 different mappings of the Function keys (Standard TK-II, or DarkAKI).

 

Not really. But it does provide a nice place to put the PS/2 jack without modification of the case other than a slight enlargement of the existing hole.

 

It has been many years, but IIRC, the original Transkey installation was no punk job.  I'd done a ton of ram upgrades and in comparison the Transkey install was fairly involved.   This new one is much neater.