This guide explains how to create a switch interface for retro computers and games consoles that used D9 controllers (those which have connectors with 9 pins in a D shape). With an additional "Stelladaptor" (see below) you can connect this interface to your PC or Mac.
SAFETY: Always use home-made equipment under supervision, and disconnect power when not in use. These adaptations are at your own risk. Good luck!
Almost all of the following components are commonly available from Electronics stores such as Maplin Electronics, apart from D9 joystick extension leads. These are available from www.stack.co.uk - who will make up a 1.8metre D9 joystick extension cable (male to female) for £2.50. Sales@stack.co.uk.
Buy pre-made: You can buy complete and ready to go retro D9 switch interfaces from the OneSwitch shop.
Drill 5 x 1/4" holes on the top for the 3.5mm sockets (main picture).
Make 2 holes for the D9 sockets (inset picture). Use a combination of drill, soldering iron, knife and files to make fairly neat D shaped holes.
As not all sockets are connected alike, you will need to find which 2 of the 3 contacts you need to solder to.
Attach a test lamp or multimeter to any 2 contacts. Plug in your switch, then press it. If the lamp comes on when pressed you have the right connections, otherwise try a different combination. There's only 3 possibilities.
Connect a ground loom. Leave a trailing wire sticking out of both D9 socket holes.
Ensure that you make a continuous connection through all the sockets - using the SAME connector for each socket.
N.B.I recommend using the left most solder point of each socket (as pictured).
1. UP, 2. DOWN, 3. LEFT, 4. RIGHT and 6. FIRE:
Solder 2 wires to each 3.5mm socket - one to connect to the female D9 and one to connect to the male D9.
Use the following pin-out guide to hook up the interface:
E.g. UP: Take the 2 wires from the UP switch socket. Solder one wire to pin 1 of the female D9 and the other to the male D9.
For pins 5, 7 and 9 - solder a piece of wire straight from the male D9 to the female D9.
Screw everything back together firmly - ideally, use nuts and bolts to secure the D9 connectors.
Find a game that uses all functions of the joystick. Plug the interface into your games machine or computer. Connect a joystick to the interface, and test that the joystick still functions correctly.
Now use a switch to test all five sockets are functioning correctly. Any problems - disconnect, and restudy the quality of your soldering. Use the soldering iron and soldering braid to remove, then resolder any poor joints.
With an AtariAge.com "Stelladaptor" you can connect this retro switch interface to your PC or Apple Mac.
D.I.Y. Text and images PUBLIC DOMAIN 2003 - www.OneSwitch.org.uk
D9 Switch interface PUBLIC DOMAIN - 1995, 2003 - Barrie Ellis
Stelladaptor (c) 2004 - AtariAge & Pixels Past