Odyssey 2 - Joystick Repair

I recently started going through the Odyssey 2 units I have to test them all out. I had a few joysticks that weren't working well so I decided to dig into how to service them. Unlike most joysticks of this era these can be a little tricky to work ok.

To disassemble the joystick first remove the two screws from the bottom which will allow the top cover to be removed. You can see how dirty the ones I worked on were.

If you want to remove the cable it has a connector that just pushes on to a row of contacts on the flex circuit. To remove this hold down on the flex circuit right by the connector and gently pull the connector off. 

The plastic knob on the top of the stick is just pressure fit, at least on the ones I worked on. To get it off I held the joystick shaft with one pair of pliers and pulled the knob off with another set of pliers. 

Disassembling the actual stick assembly is the trickiest part of this repair. It is held together by a locking washer which fits into a groove on the shaft. To get this off, push down on the black part to compress the spring and give some room to access the lock washer. Grab the lock washer with a pair of needle nose pliers and gently bend it down to spread the teeth on the inside, this will give just enough room to pull it off. So far I have not broken one of these but it looks like replacements aren't hard to get. They are generally referred to as "pushnut washers", it would just be a matter of finding the right size. 

I have found one stick that used a c-clip instead of a pushnut. Not sure if this was a manufacturing variation or if someone just used it in an earlier repair. 

With the lock washer removed the joystick assembly comes apart. Under this you can see the flex circuit assembly. The bottom of the joystick assembly pushes on segments of the flex circuit as you move the stick which activates one of four directional "switches" in the flex circuit. 

Looking at the bottom of the stick there seems to be two variations. The one on the left has a disk that locks into the bottom of the stick to hold the metal shaft in place. Most of the sticks I have do not have this part, so it may have eventually been removed to save money. It is not actually needed since the spring pressure hold that shaft in place. 

Getting the disk off can be a little tricky. It rotates to unlock the three tabs, but each tab has a little protrusion on the bottom that locks into a slot to prevent the disk from rotating. To get it off I put a very small flat blade screwdriver under the end of each tab and pried up carefully to release tab. After doing this to each one I use a pair of needle nose pliers placed in two of the three tabs to rotate the disk. 

Here is what the disk looks like when removed from the stick. 

I was recently working on a pair of sticks which had a odd feature. The one on the right is a "normal" stick which has a ridge around the top of the cylinder that hold the metal shaft of the stick in place, you insert the stick from the bottom and the ridge keeps it from coming out the top. The one on the left is missing this ridge so you can actually pull up on the stick. Both sticks were like this so I don't know if this was just wear or if there was a reason this ridge was removed. 

In general these sticks are built pretty well, so if anything it is going to fail it is the flex circuit. I have seen two different failures of these, damage to the traces on the flex circuit creating an open to one or more of the switches, or one or more of the switches being stuck on. 

You can test the switches with an Ohm meter, measuring between the Common and one of the other traces. The traces are pretty fragile so be careful not to scratch them up too much with the meter probe. It may be best to leave the connector connected and measure from contacts on the side of the connector. 

So far when I have found opens in the traces it has been right at the bend where the edge connector enters the rest of the assembly. To repair this I used a conductive pen I found on Amazon...

https://www.amazon.com/dp/B00OZATJ3A

Just cleanup the traces with some alcohol and then draw over the break with the pen. For the one I was working on it look a few passes with the pen to get it to start working, just give it some time to dry between each pass. 

The other failure I saw was one of the buttons being stuck on. To fix this I carefully heated up the flex circuit with a hair dryer and pealed the two layers apart near the switch that was stuck. Once I had it unstuck I pressed the layers back together. This did fix the problem, although I don't know if it will stay fixed when the stick is used. 

After repairing the flex circuit and cleaning all the parts I reassembled the sticks using the reverse of the disassembly procedure.