1200xl Keyboard not working.

[KLund1]

Hi all,

Got a used 1200xl off ebay in very good condition. Problem is the keyboard. None of the keys work. If I take the keyboard apart; the mylar pcboard from the key frame, leave the pcboard attached to the computer, the pcboard works when I press the contacts, for all keys. It seems that the small clear rubber tip of the keys do not press hard enough down to make the contact. I've read the post here about cleaning the mylar contacts, but I'm not sure that applies here. If I leave the pcboard attached, and put the keyboard frame on it lightly, I can get some of the keys to work. There are 2 little tips on the keyframe that are there to line up the pcboard. There is about 1/64' play in moving the pcboard around the keyframe. Moving the pcboard 1/64 left, right, etc dose not get any working keys. If I screw the pcboard to the keyframe, and do not tighten them down hard I get a few keys to work in all rows. Wiggling the keys makes no difference.

I'd rather not send the $45 for a new keyboard at B & E, even though he is only 3 blocks from my work.

Any suggestions?

Thanks

KLund1

[MEtalGuy66]

YES!

 

it's amazing that you ran acros this tonight. I just fixed one that had the EXACT same problem yours has..

 

Obviously, since all the mylar contact pads work fine without the keys, it's not a case where it needs Bob's famous "keyboard tuneup"...

 

In the past, Ive run across several 1200XLs that even after the "keyboard tuneup", and meticulous cleaning of the contacts, several keys had "problems"..

 

heres the solution:

 

As he stated above, the problem is the exact place that the nylon "tips" are contacting the pads..

 

Heres what you do.. take the PCB/MYLAR back off of the keyboard mech.. Now, look at the back of the keyboard mech.. There are two tiny plastic "allignment pins".. These serve to line the PCB up exactly with the plastic keyboard mech..

 

CAREFULLY remove these two allignment pins with a small file, or razor blade..

 

Now, put the PCb back on the keyboard mech and start all the screws, but leave them loose..

 

Now. with one hand, push the PCB as far as it can go towards the TOP (function key) end of the keyboard mech. While holding it firmly pushed that way, tighten up all the screws, starting from the end you are pushing on, and ending up at the TOP (function key) end..

 

What yopu have just done is MOVE the points at which the nylon "tips" contact the mylar pressure pads by about .010 - .020 inches...

 

THIS MAKES A FREAKIN WORLD OF DIFFERENCE... It will work like brand new..

 

Anyone who's got 1200XL keyboards witha few flakey keys that theyve basically "given up" on, should TRY THIS NOW!

 

Ive fixed two of them like this that I had previosuly tried EVERYTHING on and given up..

 

And both of them work like brand freakin new..

 

 

Someone should add this to the 1200XL keyboard repair docs, becase it really does make a HUGE difference...

[KLund1]

IT WORKS!!!!!!!!!!!!!!!!!

 

Just followed you instructions! BOOM!!!! New Computer!!!!

 

All keys work as they should. Took about 3 minutes to do and test.

Be careful which way you apply pressure during the screw tighten. I can see where putting pressure in the other direction might be helpful in some cases.

But this WORKS!!

 

Admin, please add this procedure to keyboard repair sticky. This will make a lot of Atari Users happy.

 

Thanks a lot for posting this quick fix!!!!!!

 

KLund1

[MEtalGuy66]

Yeah its funny how peoples minds work in paralell sometimes.. I was messing with a 1200XL tonight that a friend let me borrow to test a new interface adaptor I made.. The keyboard hadnt been used in years, but looked brand new, and half the keys wouldnt work.. I took it apart and noticed the same thing you did.. All the damn contact pads worked perfect without the actual keys.. When I peeled back the mylar, the contacts looked clean & perfect.. So I got to thinking.. What the hell is going on here?

 

Thats when I had the idea to move the relative contact points slightly.. I guess you could accomplish the same thing by replacing the Mylar.. But hell, with this method, you might get 10 more years out of the existing mylar.. and then, if it flakes out again, loosen up the screws and "push" the PCB the opposite way.. It'll probably achieve the same effect.. The contact pads are pretty huge by comparisson t the actual nylon "tips".. So youve got "miles" of room to "adjust"... Your only limited by the tolerance of the screwholes in the PCB..