Is it possible to bend tension back into Atari 2600 joystick contact domes?

Question

So I got these two Ataris, just got them working. I was testing out the controllers and most of them have problems with the joystick not reacting. I opened them up, cleaned them, still have the problem. Than I pushed down on some of the contacts and realized they didn't have any tension. So can I bend them back or should I just suck it up and pay 25$ to buy 25 contacts off eBay?

Answer 1

TLDR; Yes you can bend them, don't bend them too much and don't flatten the dimples.

First be sure the contact disk is the issue.

If the problem is intermittent, You can also remove power from the Atari and spray plastic safe contact cleaner into the controller socket and system pins and then insert and remove several times to clean up those connections.

Next the board to cable connections should be re-flowed with new flux or remove and replace with some new flux and fresh solder to firm up those connections. Once you are sure of those connections you can check the discs by clipping an ohmmeter the board edge and testing the pads directly.

The disc works by connecting the outer loop to the center pad and IR remotes of later eras used interlocking contact fingers and a conductive pad to do the same trick. Over time both types suffer from oxidation on the exposed contact area preventing electrical contact across the switch. That hard nonconducting layer will build up on the surface and then get transferred to the other surface which is also going though the same process though at a different rate because to the different metal.

I'd consider the disc the issue if the symptom is constant activation. Although I guess if pressing the disc center causes the edge dimples to lift that could be a problem too. Lightly bending the disc will give a stronger response for a time. Try not to make a hard crease. They were pressed out of a mold to be formed but whatever you do don't flatten the any of the dimples. That would make contact area much less effective.

If your symptom is no response on one or two pads - they are not detecting and that is almost certainly oxidation. You can verify that is the problem with an ohmmeter on the pins at the edge of the board.

***Note: I have not looked at these forever and don't recall for sure the contact area trace material on the board. If its carbon then you don't want to use any mechanical cleaning methods just want to use some carbon safe electrical contact cleaner. Carbon contacts are almost impossible to fix without luck and far more practice than you have if you are asking this question.

Repair attempts vary, but it does not hurt to try if as the other poster mentioned there is a replacement PCB with gold contacts available. Cleaning is only going to solve the issue for a time. Eventually the contact area will oxidize again. How quickly depends on your environment.

To clean use light short strokes in one direction with a soft pink art eraser on both contact surfaces and the disc. Prior to reassembly clean with a zero-residue contact solvent to clean up any oils from handling before immediately reassembling. If the eraser is getting dirty you move to a clean surface on the eraser or trim it with a knife otherwise you are just pushing dirt back onto the board. If the eraser is crumbling you may be pressing too hard.

You absolutely do not want to use a hard (usually white) ink eraser which is far to abrasive for this task.

The eraser works by taking off the top oxide layer and if you rub too hard probably some of the base metal as well. Eventually after many cleaning cycles to you will remove enough metal to damage the trace. If you do this with gold plated contacts you can also abrade thought the plating negating its use.

Answer 2

We used to replace the domes with half razor blades (split in half along the long side). The blade can be attached in the center, below the metal ring, and right there you can put a little bit of paper to lift it up. It was a lore more 'loose' than the original contact dome, but it was durable.

Answer 3

Best Electronics have replacement PCBs with gold contacts. Might be worth a look at their web site.