1200XL Keyboard Repair - One week later

[+BoatofCar]

So I did the repair described here:

 

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

 

And everything was great for about a week. Today I fired up the machine, ready to go with my new MyIDE][, and the A-row of keys is no longer functioning. How does this happen?

[ACML]

So I did the repair described here:

 

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

 

And everything was great for about a week. Today I fired up the machine, ready to go with my new MyIDE][, and the A-row of keys is no longer functioning. How does this happen?

It happened to me, but rest easy, the solution is simple. When you built up the conductive terminal ends with conductive paint, it was a raised some amount. That being, the conductive paint is thick and you had to put enough to also replace the tape spacer that you removed and discarded. That's the 1/4" by 2" piece of tape that was sandwiched between the mylar and PCB terminal contact points where the mylar mates with the PCB. What's happened is that the one terminal trace that constitutes the "A" row was not built up enough. All the others are making contact, but the "A" row just "missed it by that much" (holding index finger and thumb as close together without touching). You need to disassemble, build up the terminal trace for the "A" row a little (just the terminal end that will touch the PCB when it dry).

There is a second possibility. You could have broke the mylar trace on that row when you pulled it off to fix. When you disassemble, make sure you put a multi-meter on that trace and verify continuity from the terminal end to all keys pads on the "A" row. You may have to use the same conductive paint to repair a cracked or torn trace on the mylar.

 

Don't give up!

Edited February 2, 2014 by ACML

[+BoatofCar]

Thanks for the encouraging words! I'll go to work with the multimeter today.

[+BoatofCar]

Ok, up and running again! I guess I put the circuitwriter pen ink on a little thick on that line and it bled over (I guess I didn't let it dry enough) when I put the mylar back on the circuit board. Got rid of the short, and everything's great! Thanks again, ACML.!

[+rockdoc2010]

well my first repair went great! 100% first time out!

 

second keyboard required a little more work but it revealed a new product "BARE CONDUCTIVE ELECTRIC PAINT"

 

A few damaged traces due to hasty removal of mylar.. its carbon based and is easier to use, not runny and dries quickly

 

so my second keyboard ROCKS as well!

 

two fully repaired keyboards thanks to BOB1200XL

 

Third one will be the charm!