Repairing a TAC-2 with a broken stick

If Commodore 64 is one of the most classic home computers from the 1980s, then Suncom’s TAC-2  (Totally Accurate Controller MK2) joystick is one of the most classic joysticks of all time, known for its precision and robustness. The TAC-2 is almost indestructible apart from some corrosion issues, and problems with old broken wires, both with can be easily fixed. However, there are a few examples of users that have managed to break the stick (I have no idea how!). Anyway, in this post we will show how to fix the broken stick. We use the American model of TAC-2, which can be separated from the less robust Chinese model by the following characteristics:

• The text beneath the joystick reads “Made in USA” and “Made in China” respectively
• The American joystick has a chromed stick, the Chinese black plastic
• The American TAC-2 has orange buttons, the Chinese red

Repair of the TAC-2 has been discussed earlier at Atariage:s forum and Haxor.fi.

Inside a TAC-2

You open your TAC-2 through three screws. The construction is simple, but robust. The stick consists of a tire valve with a metall shaft and ball that creates a connection when you move the handle. Suncom’s patent for the construction is dated 1984 and can be found through Google Patents or via this PDF: Joy stick switch. This is the stick I want to replace in this post, with a little (read: a lot!) of help from my father in his smithing workshop. During a few days we tried some different methods to fix the stick. I ordered a few TR-418 valves from a Swedish site that specialize on spare parts for foresting machine tires (quite cool that you can buy joystick spare parts from this kind of shop!). The valve is actually one of the things that contribute to the good reputation of the TAC-2: it adds to precision, and make sure the stick is centering properly. In the picture below we measure the part of the stick that comes out from the valve.

You have to disassemble the broken joystick. Cut the tire valve and loosen the plastic collar on top (it might break, but is available for 3D-printing). The plastic knob at the top of the handle can be unscrewed with some force (also available for 3D-printing).

TAC-2 repair part 1: parts!

To repair the TAC-2 stick, we have used the following parts:

TAC-2 repair part 2: Prepare the valve and the screw eye

We want to attach the screw eye in the tire valve, but the threads are too big. We grinded them down until they fit the bottom of the valve. To make sure that the fit would stick, we prepared the grinded part with some super glue, and hammered it into place. Then we, sawed the screw eye off in a suitable length measured above.

  

TAC-2 repair part 3: Attach the metal ball in the cut screw eye

Dislocate the broken shaft from the original ball completely with a saw. Then you will need to drill a hole in the ball, which should be slightly less than the diameter of the shaft of the screw eye. You need to get the hole as straight as possible, to ensure future gaming precision! To attach the ball on the stick, jam the valve into a vice with “soft” holders that wont hurt the rubber, and use a hammer! If the hole is to tight, use a file or a dremmel to widen it a bit.

TAC-2 repair part 4: Attach the stick in the joystick housing

Now you have a complete stick that you want to attach in the upper part of the joystick housing of the TAC-2. This is accomplished by pushing the stick through from below, add some moisturized that will easily vaporize (we used soap), and hammer on a pipe that matches the size of the rubber valve. Be careful not to damage the joystick during this step!

Now the hard part is over! Clean all surfaces and assemble your TAC-2 back together again! if the plastic knob has a poor fit, use some epoxy or similar to attach it properly to the stick. The repaired joystick has a bit more range of motion than the original since the stick do not have a chrome cylinder. The repaired stick feels excellent though!

In addition, we forged some new balls in brass, and attached a chromed copper pipe on another shaft. This process will be described in a future post!