600Xl keyboard Issues

[darkxavier]

Hi

Bought myself an 600XL today from a carboot sale. Most of the keys work apart from A,S,D,F,G,H and both shift keys and control key. Opened it up and removed the ribbon cable, cleaned it with an eraser but still no joy. Is there anything else I can try?

 

Thanks

[AtariMusicNet]

I'd have a look at the tracks on the keyboard itself and look for any that appear broken. Some keyboards are prone to things like that with age.

 

 

Sent from my iPhone using Tapatalk

[spookt]

There's a discussion in the restoration sticky at the top of this forum about keyboard repairs. It's 1200XL specific, but the concepts apply to the other mylar based Atari keyboards. You may find that all the faulty keys are on the same line. One break in the track and they stop working.

 

The other favourite repair procedure is to hit the none working key repeatedly. This usually eventually cleans oxidised contacts but probably won't help on a 600XL. Worth a try before you rip open the keyboard.

[yorgle]

The 1200xl repair thread won't help you as it's an entirely different keyboard than the 600xl and 800xl. The symptom you describe is most likely a broken trace on the pcb which can be found by testing continuity between keyswitch solder points along the same pcb trace. Look closely for scratches on the pcb that cross a trace. Even a tiny scratch can break continuity. Once you find the break, repair is simply a matter of scratching off the green coating from the broken trace and soldering the gap closed or, if the gap is small enough, you can try scratching over the gap with a small sharp object to mash the copper back together. That worked on one of my 600xl's. Another place where continuity can get lost is where the keyswitches are soldered to the traces. Fixing that is simply a matter of remelting the solder. Good luck.

 

Another possible source of the problem is a broken trace inside the ribbon cable (usually where the cable is folded). Check continuity between the points on the pcb where the ribbon cable mounts and the exposed ends of the cable. A broken trace in the ribbon can be repaired by simply soldering a small piece of wire or foil to bridge the break.

 

The final place to look is where the keyboard connector is soldered to the main pcb. The connector is flexed everytime the keyboard is removed so it's possible that a solder connection to the main pcb is broken.

Edited May 2, 2011 by yorgle

[puppetmark]

Hi

Bought myself an 600XL today from a carboot sale. Most of the keys work apart from A,S,D,F,G,H and both shift keys and control key. Opened it up and removed the ribbon cable, cleaned it with an eraser but still no joy. Is there anything else I can try?

 

Thanks

 

Does the keyboard have a printed circuit board or a metal plate that holds a mylar sheet in place?

[darkxavier]

Hi

Bought myself an 600XL today from a carboot sale. Most of the keys work apart from A,S,D,F,G,H and both shift keys and control key. Opened it up and removed the ribbon cable, cleaned it with an eraser but still no joy. Is there anything else I can try?

 

Thanks

 

Does the keyboard have a printed circuit board or a metal plate that holds a mylar sheet in place?

 

It has a mylar sheet held in place by a steel sheet.

[puppetmark]

Hi

Bought myself an 600XL today from a carboot sale. Most of the keys work apart from A,S,D,F,G,H and both shift keys and control key. Opened it up and removed the ribbon cable, cleaned it with an eraser but still no joy. Is there anything else I can try?

 

Thanks

 

Does the keyboard have a printed circuit board or a metal plate that holds a mylar sheet in place?

 

It has a mylar sheet held in place by a steel sheet.

 

there is probably a broken trace on the mylar, but first ( in case it is just gunked up with something ) I would remove all the screws, clean all the mylar sides, including the clear center sheet with isopropyl alchohol and let it dry thoroughly, reassemble and try it again.

 

If it still doesn't work then take it apart again. ( sorry about the sore wrist - its a lot of little screws I know! ) Then try putting the mylar up to a very bright light but not close enough to melt the mylar from a hot lamp! Better still would be a light box if you have access to one. A magnifying glass may also come in handy here. If / when you find breaks in the mylar they CAN be fixed with conductive paint. The stuff used for repairing rear window defrosters from an auto parts store works but you will need a very fine and good quality paint brush from an arts and crafts store. Take your time as it takes some steadyness. Reassemble and give it a go.

 

I have repaired sveral keyboards this way, so I know it works.