a little bit of nothing...

Rewiring a digital joystick

First posted on May 15th, 2004

The Atari 9-pin D-type was the most popular joystick connector of the 80s, used in many consoles and home computers, like the Amiga, the Atari ST, the Amstrad CPC series, the C64, the Sega Mega Drive etc. If you have a joystick from that time, chances are that the wire connections will have suffered a lot and will probably start to abandon you. This happened to me at least, and I had to connect a whole new wire to my joystick. This would of course be a very easy task for a qualified technician, but for me it was a bit of an adventure. Here is the whole story :)

joystick pic joystick pic

The joystick I use is a MicroTechnica ACS. It's one of the many quality arcade-style joysticks that were made in Greece during the 8-bit and 16-bit computers' reign. The ACS is a very durable joystick, heavy, with a metal case, a short metal stick and quality microswitches. The firebutton isn't so well made and I have replaced it twice, but the rest of the mechanical parts are very reliable and never caused me any problems. A quite rare characteristic is the inclusion of a connector for a second joystick on the case; this is because the ACS was originally made for the Amstrad CPC series of home computers, which had only one joystick port (they were very cheap though, remember?)

After many years of operation (I bought the joystick in 1986) I started having various reliability problems with the joystick; the down direction and the fire button sometimes didn't respond. This could be fixed by moving and bending the wire, therefore I concluded that it had to be replaced. So the adventure begun.

The first step was to get a diagram of the joystick connector. The Hardware Book (http://www.hardwarebook.net) of course had the answer. So, by studying the diagram, I realised that I needed a cable with at least 6 wires (up, down, left, right, fire and ground) and of course the connector itself, a 9-pin D-Sub female connector.

Joystick pic

Before moving on, let me make a small description of how the joystick works behind the hood. I'm sure that electronics-savy people will find my description offensively simplistic and they will be right, but still it may be useful for people with no prior knowledge on the subject: By saying that the connector is a 9-pin D-Sub, we mean that it is D-shaped and at maximum 9 wires can be connected with it. In the controller itself, next to the stick, there are four switches, placed in such a way that they are switched on (= allow current to pass) everytime the joystick is moved to one of the up, down, left and right directions. Diagonal directions enable two microswitches at the same time. Each one of these microswitches is connected to a small wire (directly or through a circuit), which in turn is connected to one of the pins of the connector. The diagram shows us which direction should be connected to which pin. Apart from the four pins needed for the four directions, we also need one more for the fire button and one more for grounding, so that's a total of six. In my joystick, the wires weren't directly connected to the switches, but to a small circuit board, to which the switches were soldered.

Parts pic

But enough of that theory, let the action begin! I bought the required parts (cable and connector) from the local electronics shop and put them on my workbench, along with the tools (a soldering iron - whose tip wasn't really the most suitable for the job, a wire cutter, a Dremel drill just in case and a set of small scredrivers), to start the operation.

Connections pic

The old cable had to be removed first. I opened the joystick and located the connections that had to be de-soldered. There were more than 6 wires connected, because of the second joystick support, but the extra wires were connected at a different part of the circuit. After heating the soldering iron, I carefully touched the iron's tip to the tin of each connecting point for less than a sec and quickly removed the respective wire. After all six were gone, I pulled the cable and removed it completely from the joystick, thanking it for its service all those years.

Cable pic

Then, I started preparing the new cable. I had to remove the protective coating from each side and then peel six wires of the same colour from each side (around half a centimetre) to prepare them for soldering. This requires some patience and precision - fortunately, the cable I had bought had 10 wires in it, so the two mistakes I made, cutting of 2 wires instead of peeling them, didn't force me to start the procedure all over again. The next step was to curl up each wire's filaments, to avoid potential problems with wires touching more than one connector after soldering.

Connector pic Connector pic

After consulting some beginners' guides on soldering, I found out that before the actual soldering, I had to tin the wires, meaning I had to apply a very thin coating of tin to each wire. The procedure for that is to warm up the iron, touch the iron's tip and the tin to the cable for a fraction of a second so that the tin melts and remove the iron and the tin in a single move. Several minutes later the cable was ready and I had to start the actual soldering to the connector. This would normally require an iron with a smaller tip than mine, and also a way to hold the connector firmly placed somewhere, so that all soldering is precise. After some improvising, I managed to solder all six wires. I noted the colour-coding (all wires have a different colour, so that we know which ones to solder to which microswitch on the other end) and got ready for the connections on the joystick end.

Tining was the next easy step, but after that I had to make a decision; was I going to solder the wires to the circuit board, as it was before, or directly to the switches? I've seen other joysticks where the wires were soldered directly to the microswitches and this required less precision soldering, so it was quite tempting. I've heard though (is that right?) that joysticks with a circuit board are more reliable, and I decided to go to this route. After all, this circuit board was included for some reason, right? :)

Joystick pic I identified the soldering connections for each one of the wires and started the process. It took me around 30 mins to finish will all the connections, but the end result seemed good enough. Alas, it wasn't going to be so easy... testing proved that nothing worked! After a lot of testing, I found that the line on the circuit board connecting the grounding pin was broken somewhere in the middle. To deal with that, I used a little piece of wire to connect the ends of the line. After that, everything worked correctly - my joystick was back from the dead. Now I have no alibi for losing in Kick Off :)