A New Best Atari 1200XL Keyboard upgrade Internal Mylar

 

We at Best have known for many many years the Atari 1200XL Keyboard internal Mylar problem which will slowly cause the Atari 1200XL keyboard key functions to go bad (nothing would register when the key caps were pushed).  The older the 1200XL Keyboards got, the more 1200XL key functions would fail.  With our 25+ year experience with Atari 65XE and Atari 130XE keyboard replacement mylars we have sold in the last 33 years, we knew how to fix the Atari 1200XL keyboard internal Mylar problem.

                           

Robert M. of MI.  Robert ordered one of Bests just released after 8 months work, New 2016 Atari 1200XL upgraded replacement Internal Keyboard Mylars. "1200XL keyboard mylar worked great, my keyboard now works again after many many years of being broken.  Thank You!"

                       

The problem was all of the companies we have contacted for the last 20+ Years all required a Min. 1st production run of a New Keyboard mylars in the thousand and thousands qtys, besides the new keyboard mylar punch and silkscreen tooling costs ($,$$$) which have to be paid up front.  We did the math and all companies we contacted over the years, the cost of a new 1200XL keyboard mylar production run was simply not cost effective to make.  If we sold the new Atari 1200XL Keyboard mylars for the next 15 to 20+ years we would never even break even on that Atari project.

                        

Recently we were very lucky to find a new Mylar manufacture who was willing to make small productions runs at a reasonable end cost.  So we started to work with them for over 8+ months, on a New Best State of Art upgrade Atari 1200XL Keyboard mylar.

                

After studying the Atari 1200XL keyboard failure problem for so many years we found the main reasons why they almost 100% fail with enough time.  The carbon dots and carbon circuit traces on the 1200XL internal Keyboard mylar would glaze over with enough everyday use (or years of lack up use) and go from a few ohms resistance across the conductive carbon dot to Meg ohms resistance.  So the higher resistance across the carbon dot, the less and less the Atari 1200XL computer would see the keyboard key cap internal switch closure.  Any old Atari 5200 Joystick owner will tell you the same problem happened with the carbon dots pads inside the Atari CX52 Joystick Fire buttons, Start, Pause, Reset and numeric keypads.  You can clean the old CX52 joystick Carbon dot pads over and over, they would work for a little while and then they would go bad again fast.  As thousands of 5200 owners have found over the last 25+ years, cleaning the carbon dots was a temporary fix, the only way to cure the old carbon dot problem was to replace the 20+ year old 5200 carbon dot pads with either new carbon dot pads or Bests lifetime Gold dot pads.  Like on an old well used TV Remote Control with the same carbon dot technology, eventually well used functions on the RC controller will slowly go bad as the Carbon dot resistance went up.  So those Atari 1200XL owner’s who cleaned their old 1200XL keyboard mylars and managed to get it working again, they are just ticking time booms which will eventually go bad again with more time and use or lack of use.  The final cure is to replace the old Atari carbon dot 1200XL Mylar with the State of the Art Best 1200XL all Silver conductive dots and traces.

 

Andrew M. of IL  Andrew ordered one of Best Exclusive Upgraded / Enhanced New 1200XL Keyboard Mylars.  "Just wanted to say thanks - 1200xl keyboard works like new.  1200xl is a joy to use with the mylar from Best Electronics!" 

         

Another problem that causes Atari 1200XL internal Mylars to go bad, was the white silk screened safety coating (keeps things that fall thru and onto the keyboard mylar from scratching conductive traces all over the complete mylar and also keeps the traces from over flexing and cracking during normal keyboard use) on the 1200XL keyboard mylar was an air cured safety coating that out gasses a chemical that also coats the carbon dots on the Internal 1200XL keyboard Mylar. 

                          

The last problem on the old atari 1200XL Keyboard internal Mylar design was the many many air channels all over the keyboard white mylar (see the white stock Mitsumi 1200XL Keyboard picture about 7/8 way down this page).  They would allow outside air in that would oxidize the carbon dots, moisture in and with the out gassing from the white safety internal coating to spread all over the different conductive keyboard mylar dots.  See the black diagonal / angled black air channels all over the stock mylar.

                       

By the way the manufacture that made the Atari 1200XL Keyboard (and it internal Keyboard mylar) is the same Atari Keyboard Manufacture that made the one version Atari XE Keyboard and internal Keyboard mylar that has a near 100% failure rate of the internal XE mylar.  The same better Best made replacement XE Keyboard mylar with all silver conductive dots, traces and translucent safety coating has about ¼ of 1% in use failure rate based on selling them to Atari XE keyboard owners all over the world for over 25+ years now.

                       

Our new Keyboard Mylar manufacture looked over the old Atari 1200L keyboard design and 1200XL keyboard mylar samples we sent them and started to make a new replacement mylar for Best.  The New 1200XL Keyboard mylar would have a New light Green State of the Art UV Cured safety Mylar coating (Guaranteed no out gassing after the UV curing processing) and a white paper insulation backing.  The Green safety coating also will seal each of the silver conducts pads on the Best 1200XL mylar from the exposed outside air.  Also this Green coating covers all of the keyboard mylar conductive silver circuit traces, which keeps them from over flexing and cracking from normal Keyboard mylar flexing over many years and years of use.   When our Keyboard Mylar manufacture made the 1st version 1200XL Keyboard prototype mylars with the above features.  When Best saw the 1st version prototype 1200XL Keyboard Mylar samples (sent pictures only, no samples received) with carbon dot technology, we told our keyboard mylar manufacture, based on our 25+ year experience with the both versions of the 65XE / 130XE Keyboard mylars with the Silver traces, will outlast the Carbon Dot / Trace type of Keyboard Mylars by about 20+ years of normal everyday use.  The 2nd version prototype 1200XL Mylar Best (received pictures only again, no samples again) had all silver conductive dots and traces, but had the air channels that still crossed thru screw holes that exposed the conductive silver dots and traces to the the outside air.  We told our Mylar Manufacture, the new Upgraded Atari 1200XL Best Keyboard Mylar is to have No air channels that are exposed to the outside air / world.  When Best received the 3rd version prototype physical samples to run functional tests on, it was found that none of the 3rd version prototype 1200XL Mylars did not function at all.  Even though our Keyboard manufacture used current 2016 state of the Keyboard mylar Technology to produce 3rd version 1200XL Keyboard mylar, it did not work in the 25+ year older technology Atari 1200XL Keyboard design.  After studying this non functioning 3rd Prototype samples for a week or more, Best came to the conclusion the problem was with the 9 interface silver fingers on the new 1200XL Keyboard flexible Mylar was not making proper contact with the 1200XL Keyboard Hard PCB mating 9 interface fingers.  To fix this Mylar Interface problem Best came up two cures. We designed (of course a brand new tooling cost to the project) a very very small wafer thin interface PCB board (two different version prototype samples made) with 9 Gold plated fingers top and bottom side of the wafer thin PCB.  

 

The top and bottom Gold plated fingers on this very small interface PCB board are electronically connected together thru two plated thru holes per finger.  So this small ultra thin sandwich Interface card is designed to sit between the new 1200XL Keyboard mylar 9 interface silver fingers and the larger 1200XL PCB backing board with it 9 interface fingers.  As extra redundant Insurance, Best had our Keyboard manufacture triple screen 9 silver interface on the 1200XL Keyboard mylar in a effort to add extra thickness on the interface fingers on the 1200XL keyboard mylar.                                            

1200XL Keyboard Mylar

prototype, 3rd version below

                                     

                                        

Top picture and bottom pictures are of the 3rd version non functioning prototype sample 1200XL

Keyboard mylar.  Top picture of the 1200XL Keyboard board mylar is the side that sits against the black 1200XL Keyboard black body with the black key plungers.

               

 

Conductive / Inner side of the Best 1200XL Keyboard Mylar that sits against the green PCB board with the  circuits traces and the gold round keypad dots.

                              

 

Top and Bottom pictures are of the 4th version fully functional prototype sample 1200XL

Keyboard Mylar.  Best had our Keyboard Mylar manufacture remove white paper backing that was

 on the 1st, 2nd and 3rd prototype keyboard mylar samples and required 3 to 4 more changes

to 12X00 Keyboard mylar before it passed all of the different diagnostic and functional

tests that Best ran on all 4th version sample 1200XL Keyboard Mylars received.

 

 

 

Note that all of the silver conductive round dots (contact for each key plunger) on the new Improved /  Upgraded Best 1200XL Keyboard mylar are sealed from the outside air by the thick light green safety coating around each conductive silver dot and circuit traces. 

 

Best Electronics over the last 25+ years has successfully made about 8 to 9 different Upgraded Atari keyboard replacement Mylars with little or no prototype sample problems at all.  With the problem after problem, 8+ months of work, the original tooling charges, the 3 to 4 new tooling charges with each new change / upgrade which had to be paid up front with bank transfers with bank fees), the new white paper insulator sheet punch tool that had to be scrapped out, the new small wafer thin Interface PCB board and the incoming recurring sample shipping charges which Best had to go thru to finally get working 1200XL Keyboard Mylar prototype samples.  Had Best made the 1200XL upgrade Keyboard mylar 1st some 25+ years ago, in most cases we would of never made any more new Atari Keyboard Mylars at all!  Now every Best 1200XL Keyboard / 1200XL Computer has now been fitted with the Best Upgraded lifetime Keyboard mylar and they are all working properly for the 1st time in the last 33 years in the Atari Business.

 

Best has made a Very Very limited One Time New production run of the New Best 1200XL upgraded replacement keyboard Mylars.

                              

The New Best Upgraded Lifetime Atari 1200XL Keyboard Mylar  CB103156 $39.95


Atari 1200XL Keyboard Mylar installation instructions

            

Top side of 1200XL keyboard black body key cap cleaning Items required:

Old Paint brush or long bristle dish brush

Spray Cleaning solution like 409

Compressed air

Hair Dryer

Several dish pans or two side by side sinks

Optional dish washer.

                     

Most of the 25+ year old non working 1200XL Keyboard key caps we have seen at Best are dirty, dusty, full dust bunny's and other strange items between the key caps.  Basically an ugly old non functioning Atari keyboard.  Best recommends you 1st clean the top side of the 1200XL Keyboard body, so it will look close to new when you are ready to reinstall back into the 1200XL top case.  Use the disassembly instructions below to get down to 1200XL plastic keyboard black body still with the keycaps installed.

 

One of the easier ways to clean the old dirty 1200XL Keyboard black body (no keyboard mylar, no green keyboard PCB board, see disassembly instructions below), is turn it upside down (over a kitchen sink) so the 1200XL key caps are facing down.  Next take your spray cleaner (spray nozzle set to stream setting) and shoot streams of cleaning fluid between all of the 1200XL key caps.  When the 1200XL Keyboard key caps are fully wetted with cleaning solution, take the soft Paint brush or dish cleaning brush and clean around all key caps.  By cleaning the 1200XL Key caps in the down facing direction, you will prevent all of the junk, dirt, dust and foreign materials from draining into the the Keyboard body and thru key plunger holes, which will cause the key plunger to possibly bind during the normal use of the 1200XL keyboard.

Note: the two different size metal springs used under the Atari 1200XL Key and function key caps are made of Stainless Steel and will not rust after your cleaning of the 1200XL keyboard top surface.

 

If your Atari 1200XL Keyboard is super dirty you may have to soak your Keyboard top body with the key caps down in a sink / dish pan filled with enough cleaning fluid (1/2 to 3/4 inch) to just submerge the key caps right to the top side of the 1200XL black body and then let is soak for a couple of minutes.  We do not recommend you soak the 1200XL Keyboard body for any longer.  The cleaning solution might start to attack the 1200XL square silver metal key caps or the old 25 year adhesive that holds metal silver square key caps into the black key plungers top surface.

 

If your cleaned 1200XL board body with the key caps are starting to look good, clean your cleaning soaked brush with clean water until you can not get any soap suds out of it.  Using a flowing stream of clean water, soak your cleaned brush in the clear water and with the keyboard in the down position start to remove / wash down all of the dirty cleaning solution until the dripping off water starts to look clear again.

 

You can now let the cleaned 1200XL black keyboard body air dry.  To speed up the drying process, shake the keyboard body several times trying to shake out as much water as possible.  Next use the Hair dryer to gently dry the inside and outside (keycap side) of the 1200XL black keyboard body.  If you have access to compressed air, blow dry the 1200XL black keyboard body.

 

Another very old Electronic Tech cleaning method for cleaning old PCB boards was to put them in a

Dish Washer.  Put the dirty 1200XL black keyboard body in the top dish washer rack with the Keycaps pointing down.  Put in some dish washing soap in and run a quick cold water or medium heat water gentle wash cycle.  Make sure you do not have your dish washer run a final heat dry cycle, but a cool air dry end cycle.  A hot final dry heat dry cycle would for sure damage or distort the 1200XL black plastic keyboard body.  

 

If after all of your 1200XL Keyboard body cleaning, if the square 1200XL silver key caps still look bad, Best has in stock, New replacement 1200XL Silver metal key covers (CO60562 $1.25 each) with adhesive backing.  

              

Installation Items required:

Small Phillips screwdriver

Small container for the Phillips screws

Alcohol or PCB Chlorinated (like TCE) cleaning solvent

Paper towels

Hair Dryer

                    

Set the 1200XL Keyboard with the keycaps are facing down.  Remove the 22 small Phillips screws (one of the Phillips screws is almost hidden from view).  It is located bottom right hand corner of the 1200XL Keyboard rear PCB board between the keyboard ribbon cable and the right top corner of adhesive black pad that holds the ribbon cable to the PCB board), off the back side PCB put them in your small container.

                                                                                                                      Red arrow = one of two black PCB aligning pins / pegs

                                                                                                                      Orange arrow = hidden PCB Phillips screw head location

                    

Before you lift the brown PCB board (with the white internal Keyboard mylar stuck to the inside of the PCB board) off the backside of the 1200XL keyboard black body, locate the two very small (1/16 inch diameter approximately) aligning black round pins / pegs that come thru the brown PCB board. They are located about 10 AM and 3 PM on the brown PCB board.  These two small aligning pins / pegs properly locate the new Best 1200XL Keyboard mylar onto the backside / inside of the 1200XL PCB board and also align the brown PCB board to the black plastic body of the 1200XL board assembly.

                   

Carefully lift the rear PCB board off the backside of the 1200XL Keyboard body.  In most cases the old Mitsumi 1200XL internal keyboard white mylar will stick to the inside to the PCB.

                  

 

 

 

 

 

If you try to remove the old white 1200XL keyboard mylar off the PCB cold, you will find, that many small and large sections of the white protective coating will peal off the 1200XL mylar and stick to different sections of PCB board.  It will end up a big clean up mess (using the paper towels and the cleaning solvent).

 

 

 

 

 

              

One method that seems to make this mylar removal process a little easier and cleaner, is to use a Hair Dryer to heat up the old Atari 1200XL Mylar that is stuck / bonded to the 1200XL green PCB board.  Gently evenly heat up the old 1200XL Mylar top white surface until it is warm to hot to the touch.  Then lift the 1200XL old mylar on one end a little and blow the hot air between the white mylar and the PCB board under it.  Slowly work your way 360 degree around the outside edges of the keyboard PCB / Mylar assembly, lifting the outside edges and blowing hot under white mylar as you go around the keyboard assembly.  Once you get all the way round the 1200XL Mylar then gently peal off the old 1200XL Keyboard heated mylar off the green PCB.  With this hot air removal technique, you might still have small chunks of the 1200XL white protective coating sticking to the green PCB board, but much much less compared to the straight cold mylar removal method.  The clean up the green PCB is much easer with the hot air removal process.                                 

             

Use the solvent to remove the rest of the white safety coating that is stuck to the inside of the green PCB.  Also use the solvent to clean each Key plunger contact Gold plated interlocking round circles / pads. Basically you want a super clean 1200XL green PCB board, that will not transfer any foreign materials to the new Best 1200XL Keyboard mylar with silver conductive dots.

                        

Very very important Information: Do not clean around the 9 interface fingers area on the green PCB (see Red box area in the picture below).  The 9 interface fingers on 1200XL PCB board have the thickness of each interface finger built up in layers so they will make proper contact with the 1200XL Keyboard mylar.  The 1200XL PCB board base 9 Gold plated interface fingers have a second silk screened carbon finger thickness and then a third Silver finger silk screened layer over the top over the carbon finger.  Best found out the hard way during the testing of the different 1200XL Keyboard mylar samples, if you clean these 9 interface fingers that have a built up proper interface thickness of conductive material, down to the hidden base PCB Gold plated interface fingers (you can not see this Gold plated fingers because each is covered by the built up silver and carbon covers) you will end up with some of the key functions on the 1200XL keyboard not properly working on the new Best 1200XL Keyboard mylar.

   

On the new Best Keyboard Mylar you will see a little white thin strip of double sided foam tape on the back side of the new Best 1200XL Keyboard mylar over / down center of the 9 silver interface fingers area.  Do not remove this thin strip of double side foam tape off the new Best 1200XL Keyboard upgrade mylar.  It is placed there so the 9 silver fingers on the new Best 1200XL keyboard will properly mate up and make proper contact with the 9 fingers on the 1200XL green PCB board.  Also there is no need to remove the top thin protective white cover off the double sided foam tape that sits against the black 1200XL black body straight plastic support bar between the two screw holes.  To install the Best New upgraded 1200XL Keyboard mylar, 1st local the 10 am and 3 pm small black aligning studs on the black keyboard body with the white key plungers facing up.  With the keyboard Mylar with the round conductive silver dot side facing up, next locate the same mating small aligning holes on the Best 1200XL mylar and then place the new mylar onto the black keyboard plastic assembly, aligning the two black studs with the two mating aligning holes on the Best 1200XL Mylar. 

 

Alternative install method. With the Best 1200XL Keyboard mylar with the round sliver conductive dots facing up, align the Best Mylar (seven function key conductive silver dots) over the top seven white Function plungers (top left to center of the black plastic 1200XL keyboard body) and also align the space bar mylar sliver conductive silver dot, over the space bar white plunger and gently lay the 1200XL mylar on the black keyboard plastic body.  With a little shifting (up / down / left and right) of the new Best Mylar on the black 1200XL keyboard body, the mylar will eventually drop on the two small aligning black pins and lock into place.

                      

Next take the 1200XL PCB board, place the green side facing down / toward the conductive dot side of the Best 1200XL Mylar (sitting on the 1200XL black body) and gently place the 1200XL PCB over the 10 am and 3 pm two aligning studs.  Next install the 22 small Phillips screws on the brown side of the 1200XL PCB board. 

 

 

 

Install your upgraded 1200XL Keyboard assembly on your Atari 1200XL computer.  Then run functional tests on the 1200XL Keyboard different key caps using an Atari Basic Cartridge.  If you have a problem with some of the 1200XL keyboard functions not working at all, then install the small wafer thin Interface PCB between the mylar 9 silver fingers and the green PCB board 9 interface fingers.  See the picture of the small thin interface PCB board about 3/4 of the way up this page


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