Atari 2600 Jr – Reset/Select Switch Repairs

1Sep/200

Atari 2600 Jr – Reset/Select Switch Repairs

I'd recently come across an Atari 2600 Jr with faulty select and reset buttons. Turns out that the mylar strip that conducts the button presses to the motherboard is toast. It doesn't conduct anything at all and I can't work out exactly where the break is.

To test if the button area even works, you can insert wires as above and check for continuity. In this case, they did, so I considered the following options to repair them.

Silver Conductive Pen

This nearly worked, but I couldn't get the paste to set correctly. The pen is from Jaycar and the basic idea is to draw a line where you want the circuit and let it set. I drew some pretty bad lines on the plastic film, but my first attempt seems to have failed as I drew the tracks too thickly. The 'ink' only becomes conductive once it's totally dry and I'm blaming winter and the fact that I don't have an incandescent bulb in the house anymore.

The next attempts were seemingly too thin. It also seems that you can't 'restart' a trace... the joint isn't conductive? Finally, the resistance seen down the track is totally erratic... but that may also be due to wet ink.

Threaded Wire

I punched a few holes in the mylar and threaded copper wire through. It was a little too stiff but, once in-place, seemed to work quite well! The main issue with this method is that, at either end of the plastic strip, adhering the wire to the conductive trace is difficult. Of course, at the motherboard end you can just jam the wires in the socket!

At the button end, you need to slip it in under the top-layer of plastic. I didn't feel confident that I could keep a valid joint and therefore didn't pursue this technique.

Microswitches

Prior to opening and testing the methods above, I was always intending on just replacing whole plastic strip with microswitches. There's a nice plastic base behind the push buttons and one could easily drill in some switches. This would also give a nice tactile experience to what is (from the factory) a really awful and mushy button press.

I went ahead and drilled holes slightly smaller than the switches. From here, I gouged out the rest of the required space as I wanted a tight fit. Of course, I was imagining things thinking that I tight fit would be enough to hold the switches in place... a hard button-press would probably send them into the case.

Therefore I glued a strip of plastic (yeah, it's a cable-tie) along the back of the holes as a backing plate for the switches. This worked perfectly! I probably should've soldered the wiring first, but it was easy enough once the switches were in position!

Once it was all back together, it turns out that the buttons were pressed in 100% of the time. To fix this, I had to drill out a section of the plastic where the button meets the switch. This worked nicely. I then decided to remove the rubber as the press was being overly-softened by it. I'd recommend you test it both ways to see which feels the best... you can also try mounting the rubber on the actual case to make sure the alignment is correct.