Atari 1200XL powers up - No LED or keyboard activity present...

[NISMOPC]

...first off.

 

THIS THING IS FREAKING ENORMOUS. EVEN THE BOX! First 1200XL I've owned and actually ever touched.

 

I am so accustom to 600XL/800XL and 65XE/130XE boxes and units I didn't realize the girth of this beauty!

 

Anyhow, unit powers up to the ATARI logo, but there is no power LED and no keyboard activity is recognized. About to open it up and check out insides, but would like some thoughts or opinions on what might be the cause.

 

In all it's glory...

 

 

[+DrVenkman]

Probaby a bad keyboard and/or the little auxiliary keyboard LED board isn't connected inside. Keyboard mylars typically go bad on pretty much all 1200XL's. They can be repaired with patience and conductive paint at the connector interface if you disassemble the keyboard. Alternately, Best sells entirely new Mylars that they have had made recently.

 

Just for basic functionality, try booting some cartridge games to test the joystick ports, and some disk software to test SIO functionality.

[NISMOPC]

Probaby a bad keyboard and/or the little auxiliary keyboard LED board isn't connected inside. Keyboard mylars typically go bad on pretty much all 1200XL's. They can be repaired with patience and conductive paint at the connector interface if you disassemble the keyboard. Alternately, Best sells entirely new Mylars that they have had made recently.

 

Just for basic functionality, try booting some cartridge games to test the joystick ports, and some disk software to test SIO functionality.

OK, so far, this is what I found. The auxiliary board was plugged in, but as I was testing with the unit apart, I saw the power light flicker on and off randomly. Powered unit off, removed the aux board and found poorly soldered LED's. Go figure. I re-soldered all 3 LED's.

 

I also checked to make sure all the chips were seated properly.

 

Powered the unit back on and the RESET button now works and the aux board now works flawlessly. Keyboard is still un-responsive, so I will pull all those wonderful little screws out and check the mylar.

 

Before and after pictures to show the wonderful soldering.

 

BEFORE (You can see right through the holes)

 

AFTER

 

POWER

Edited August 9, 2018 by NISMOPC

[+DrVenkman]

If you're willing to be patient, most 1200XL Mylars seem to fail at the connector, but the rest of the traces are usually fine - at least, that's true of all three of mine - so a little while spent removing the insulating silicone layer will let you fix the connector traces with just a few dollars worth of conductive paint and a very fine brush or even a toothpick dipped into the paint and used to trace out the contacts. Here's the tried-and-true fix I've used successfully:

 

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

 

I've done two of my three 1200XL keyboards four years ago and both of them still work great. The third unit needs to fix but I just haven't gotten around to it yet.

[SoundGammon]

Anyone have an extra set of OS roms I can copy?

 

I want to merge them into one eprom and put it into my 600XL!

 

I like the Atari logo screen!

[NISMOPC]

If you're willing to be patient, most 1200XL Mylars seem to fail at the connector, but the rest of the traces are usually fine - at least, that's true of all three of mine - so a little while spent removing the insulating silicone layer will let you fix the connector traces with just a few dollars worth of conductive paint and a very fine brush or even a toothpick dipped into the paint and used to trace out the contacts. Here's the tried-and-true fix I've used successfully:

 

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

 

I've done two of my three 1200XL keyboards four years ago and both of them still work great. The third unit needs to fix but I just haven't gotten around to it yet.

I've come to find over the years, patience is something you need when dealing with just about all Atari units...

 

...Update! With the keyboard apart and only mylar/pcb attached, I am able to use all of the keys without any issues. I was able to get into self-test and test memory and I tested all keys in the keyboard test. So, I am going to re-assemble keyboard and see what the heck is going on. This thing looks brand new inside. I see no issues with the mylar and no splits, cracks or rips in any of the lines.

 

[+DrVenkman]

Anyone have an extra set of OS roms I can copy?

 

I want to merge them into one eprom and put it into my 600XL!

 

I like the Atari logo screen!

 

Just do a forum search - both version 10 and 11 roms have been dumped since forever ago and are widely available.

[+DrVenkman]

I've come to find over the years, patience is something you need when dealing with just about all Atari units...

 

...Update! With the keyboard apart and only mylar/pcb attached, I am able to use all of the keys without any issues. I was able to get into self-test and test memory and I tested all keys in the keyboard test. So, I am going to re-assemble keyboard and see what the heck is going on. This thing looks brand new inside. I see no issues with the mylar and no splits, cracks or rips in any of the lines.

 

 

What's going on is failure at the connector - the traces wear out and oxidize over time. Changing or increasing the pressure can temporarily fix the issue, but the best/only long-term fix aside from a new Mylar is repainting those traces with new conductive paint. Automotive window defroster paint will work, as will (expensive!) nickel-based conductive paint and even super cheap Bare carbon paint.

[NISMOPC]

 

What's going on is failure at the connector - the traces wear out and oxidize over time. Changing or increasing the pressure can temporarily fix the issue, but the best/only long-term fix aside from a new Mylar is repainting those traces with new conductive paint. Automotive window defroster paint will work, as will (expensive!) nickel-based conductive paint and even super cheap Bare carbon paint.

I don't agree 100% with you. Had to test my own theory . Put keyboard back together and booted it up. Appears to be at each mylar touch point for each key.

 

If I get certain buttons to push down at just the right angle (tapping continuously with little to no force) I can get them to respond. I was able to get into the keyboard test again with keyboard installed and only 5 keys would recognize my tapping method.

 

Since this thing is in such great shape, I am going with new mylar. I've had incredible success with my other 8-bits and Best mylars, so why stop now!

 

Thanks for your input! Now my XL collection is complete!

Edited August 9, 2018 by NISMOPC

[xrbrevin]

...first off.

 

THIS THING IS FREAKING ENORMOUS. EVEN THE BOX! First 1200XL I've owned and actually ever touched.

 

I am so accustom to 600XL/800XL and 65XE/130XE boxes and units I didn't realize the girth of this beauty!

 

Anyhow, unit powers up to the ATARI logo, but there is no power LED and no keyboard activity is recognized. About to open it up and check out insides, but would like some thoughts or opinions on what might be the cause.

 

In all it's glory...

 

0809181624.jpg

 

0809181630.jpg

 

looks like you needs a bigger desk! lol

gratz on your new addition

[ACML]

I don't agree 100% with you. Had to test my own theory . Put keyboard back together and booted it up. Appears to be at each mylar touch point for each key.

 

If I get certain buttons to push down at just the right angle (tapping continuously with little to no force) I can get them to respond. I was able to get into the keyboard test again with keyboard installed and only 5 keys would recognize my tapping method.

 

Since this thing is in such great shape, I am going with new mylar. I've had incredible success with my other 8-bits and Best mylars, so why stop now!

 

Thanks for your input! Now my XL collection is complete!

DrVenkman is correct, its just the carbon traces. It appears that the issue is with the keys themselves, but nope, just repaint the connector traces and get rid of the little 2"x1/4" piece of tape that is sandwiched between the PCB and mylar and your keyboard will be as good as new.

Edited August 9, 2018 by ACML

[NISMOPC]

DrVenkman is correct, its just the carbon traces. It appears that the issue is with the keys themselves, but nope, just repaint the connector traces and get rid of the little 2"x1/4" piece of tape that is sandwiched between the PCB and mylar and your keyboard will be as good as new.

1200XL keyboard fix.jpg

Hmm...

 

well, it's worth a shot. Thank you for confirming his thoughts. I'll see if I can pick some conductive paint possibly tonight and work the magic.

Edited August 9, 2018 by NISMOPC

[jc13]

I had one where at least 3/4 of the keys didn't work at all, but I found after tapping on each of them repeatedly (maybe 50-75 times), they started to work intermittently and then eventually worked all the time. So it could just be that same type of issue, but the keyboard connector will also fail at some point...

[_The Doctor__]

to be sure, the combined issue of resistance is additive ...... the slight oxidized layer at the key will wear off and perform better over time... but add that with the resistance at the pressure connection (some refer to to as film or tape.... and you get the behaviors mentioned... do yourself a favor... repair the connection as described and the rest will take care of itself...

 

Been at this forever, as have the others... put your faith in that we are giving you a tried and true answer to a situation that WILL happen... There isn't an if.... it needs to be done. Since you are already at this point you might as well get it out of the way ... it will only prevent the haunting, inevitable conclusion later on.

Edited August 9, 2018 by _The Doctor__

[NISMOPC]

I wanted to believe, I truly did.

 

Picked up Permatex rear defogger kit with conductive paint. Used a toothpick because the brush and the stencil was too wide for this job. Unless I completely misunderstood, this is what I did. Removed the 2"x1/4" conductive tape, carefully placed new lines on the mylar where they came off, let it dry, then reassembled. The PCB contacts where shiny and clean, so I saw no reason to clean them or use the paint on them.

 

RESET and HELP work as they did before, but still have same issue with basically every other key except a random few that will work with slight tapping.

 

 

 

Bradley (Best Electronics) also got back to me already, so I am going to bite the bullet and purchase the lifetime mylar replacement.

 

Guys, thank you for all your advice and assistance. I truly wished this option worked, but I am OK with moving forward and getting new mylar...

[erichenneke]

If you're willing to be patient, most 1200XL Mylars seem to fail at the connector, but the rest of the traces are usually fine - at least, that's true of all three of mine - so a little while spent removing the insulating silicone layer will let you fix the connector traces with just a few dollars worth of conductive paint and a very fine brush or even a toothpick dipped into the paint and used to trace out the contacts. Here's the tried-and-true fix I've used successfully:

 

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

 

I've done two of my three 1200XL keyboards four years ago and both of them still work great. The third unit needs to fix but I just haven't gotten around to it yet.

 

Yep, that's exactly what I did with my 1200XL (used the rear-window defrost repair paint) and it worked like a champ.

 

I suggest you give this a try right at that interface point under the tape.

 

I doubted it would work as well when I did it, but it fixed the keyboard 100% and a year later it is still fine.

 

-Eric

[NISMOPC]

 

I suggest you give this a try right at that interface point under the tape.

 

-Eric

 

Didn't work. See above.

 

I purchased a new mylar from Best Electronics. Payment sent. Bought a few other items as well. Why not...

[erichenneke]

 

Didn't work. See above.

 

I purchased a new mylar from Best Electronics. Payment sent. Bought a few other items as well. Why not...

 

I had ordered a new mylar from best as well, but while I was waiting for it to come in I tried this "trick" and it worked so well I just put the new mylar in the closet as a "back-up I may need some day".

 

One other thing to try, while waiting on your new mylar... add a little something to apply a tiny bit of added pressure down on that interface connection point. Just a little shim or something that will assure good firm contact between the ribbon at the gold fingers on the board. If I remember correctly you will have a little piece of something that you screw back on (into the 2 screw holes on each side of that connection) when you put it back together. I put a little something extra under there before I re-assembly that...I think I cut a thin piece of plastic (from a credit card, or maybe something even thinner) and added that when I screwed it back together. Before I did that it was just partially working from the conductive painting alone... then adding a little more pressure, together, did the trick 100%.

 

Worth a try "while you wait".

[ACML]

I wanted to believe, I truly did.

 

Picked up Permatex rear defogger kit with conductive paint. Used a toothpick because the brush and the stencil was too wide for this job. Unless I completely misunderstood, this is what I did. Removed the 2"x1/4" conductive tape, carefully placed new lines on the mylar where they came off, let it dry, then reassembled. The PCB contacts where shiny and clean, so I saw no reason to clean them or use the paint on them.

 

RESET and HELP work as they did before, but still have same issue with basically every other key except a random few that will work with slight tapping.

 

0809181949.jpg

 

0809181952.jpg

 

Bradley (Best Electronics) also got back to me already, so I am going to bite the bullet and purchase the lifetime mylar replacement.

 

Guys, thank you for all your advice and assistance. I truly wished this option worked, but I am OK with moving forward and getting new mylar...

One last thought before you throw in the towel. The conductive material has to be built up enough to be higher than the thickness of the white silicon spacer. That was what the tape was for (insure contact). Trust me on this. I've had the same thing happen to me when I first started refurbishing these mylars. Add more conductive paint and build up the height so it sits taller than the thickness of the white silicon spacer material and it should be 100% good to go. In the words of Andy Dufresne, "if you've come this far, maybe you're willing to come a little further".

Edited August 10, 2018 by ACML

[NISMOPC]

I'll give it a shot. Both building up of paint and thin spacer. I saw that Best Electronics comes with a foam insert attached at the same point to put pressure down on the PCB, so it's feasible for me to attempt one last shot at it. If it works, I'll be in same place as erichenneke and have a new mylar stored away for that special moment...

[ACML]

I'll give it a shot. Both building up of paint and thin spacer. I saw that Best Electronics comes with a foam insert attached at the same point to put pressure down on the PCB, so it's feasible for me to attempt one last shot at it. If it works, I'll be in same place as erichenneke and have a new mylar stored away for that special moment...

Please don't put that 2" x 1/4" tape back in. Throw it away. You just need to build up the height of the conductive trace. Since it's going on thicker, it probably needs more time to dry before reassembly. Good luck.

[+kheller2]

It doesn’t look like you cleaned the actual PCB contacts off. There should be nothing left on there of the tape. Scrub it clean. See pic4 on the method posed above.

[NISMOPC]

It doesn’t look like you cleaned the actual PCB contacts off. There should be nothing left on there of the tape. Scrub it clean. See pic4 on the method posed above.

 

You are correct! When I pull apart tomorrow to put another layer on, I will get rid of all the residue left behind from the tape I removed. Thanks!!!

[_The Doctor__]

it's tedious but is indeed absolutely needed to make sure that tape stuff is out of there, just be super careful doing it... and by all means make sure the conductive stuff is mixed up really well... bleed through makes it appear as though it was a little thin... this is a game of mils.... so clean with a good build up is key

 

if it doesn't get the job done after that , one last coating of the fingers right up to the white might be in order....

Edited August 10, 2018 by _The Doctor__

[Sugarland]

Congrats on your new 1200XL! They are really beautiful. Use it for a few days and it'll grow even more on you and when you go back to the 800XL it will seem small.

 

A couple years ago I had to go with the Best Mylar. I tried about twelve different methods with the conductive paint and nothing worked. I tried a thick coat - nope.. I tried inserting a spacer to increase the pressure.. Nope. I'm sure it can work but I was new to restoration. Each time taking those 18 screws out, especially the one next to the ribbon cable was tiresome and I lost more hope of getting it working after each attempt. lol.. It felt like a big waste of time. The mylar replacement worked perfectly the first try.

 

Important to say though.. If you do remove the Atari mylar in hopes of repairing it, I think the trick is to warm it up with a hair drier so it peels off well without tearing.

Edited August 10, 2018 by Sugarland