There I was, in garage sale heaven. Standing over a box of second hand XBOX controllers.  I got a little less excited when I noted how second hand they were. I thought I would salvage parts and asked, "How much?".  She said, "$2". I said, "OK."  He looked like he just lost an old friend and his wife was telling herself, "I should have said 3!"

Fast forward 16 months and I'm sorting them into a box labeled "electronic recycle" because I was to lazy to open them up for salvage.  One did catch my eye,  it was an undersize wireless controller that made me think, "Can the d-pad and a trigger button be wired to plug into my Atari?"

 Fast forward another couple of months and I'm playing Star Raiders with an XBOX Controller. At least one got saved from the landfill.

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These photos were taken for reference.

  1 -   The controller was a 2.4 Ghz wireless MadCatz. (Receiver not avalible.)

2 -  The main board after removing the transmitter and battery holder.

3 -  Removed 2 screws and lifted the D-pad. 

4 -  Cut off existing wires.

5 -  Solder wire for up, down, left, right, and Ground (common). Note wire colors, mine not standard.

6 -  Contacts in placed and wires routed.   One of the cross pieces in the plastic bracket needed to be remove for the board to sit flat.  Solder joint interference.

7 -  Cut a notch in case for CX40 cable. 

8 -  Solder 2 wires for trigger switch. One for the trigger pin and one for the ground. (solder joints are for a different design that didn't work so well.  They didn't need to be moved.)

9 -  Clean off resistive material across B contacts and solder micro switch as close to center as you can.  Be sure the plunger will make contact with button.  (the wires could have been soldered to the push button switch and glued into place.)

10 -  Solder leads to joystick cable.  UP-Pin1, Down - Pin2, Left - Pin3, Right - Pin4, Trigger -  Pin6, and other side of trigger and common on d-pad - Pin8.

11 -  Because the push button was to high, the plunger needed to sanded shorter.

12 - On the upper case, the button guide required some material removal to keep from depressing  the switch.

13 -  Put the case together. Be sure wires are not pinched or interfering with button movements.

The case was opened and closed several times to make modification before the trigger reliably worked. I was really close to giving up.  There was a bit of lucky with the d-pad.

This joystick tester came in handy.  I think it saved me more time then it took to build it.