The Coin Door is fairly easy. I suggest testing the wiring before the door is mounted to make sure everything works and you have the right wires in the right spot.
The Coin Door lighting is hooked up to the PC. I took a Y-adapter for the molex connector (the 4-pin PC power standard connector) and cut the wires on one side. The yellow wire is 12V and can be spliced to a wire that you can daisychain to the two coin door lights. The black wire next to it is a ground wire. That also needs to be daisychained to the two lights. Here is an excellent simple explanation of the PC Molex configuration. I ended up soldering the wires to the coin door light connectors to make the connection more secure. Tape and twisting won't cut it. See the Power page for more details.
There is also a great coin door wiring reference page courtesy of RetroBlast.
Here is the Coin Door lighting connection:
Here is another shot of the Coin Door lighting connection:
For the actual coins registering as credits, you need to connect the coin door to the IPAC Coin 1 and Coin 2 connections. You also need to connect the ground from the IPAC to the coin connectors on the coin door, NOT the coin door lights.
Here is the Coin Door connection for the registration of coin credits (black is ground and runs to the IPAC. The green runs to the corresponding Coin1/Coin2 connections on the IPAC):
Figuring out how to replace the coin denomination inserts was a royal pain. It turns out you need to unscrew the plunger cover from the back by finding some harder to reach screws. Once you have the plunger out, then you can see there is a slot in the plunger itself where the inserts slide in and out. You need to use something firm and thin like a knife to push out the old inserts. I wouldn't recommend this unless the old inserts really bother you (which they did for me).
Mounting the coin door is also easy. Happ Controls has a Mounting View for the door that gives you measurements for the cutout. Then, test the door for size by placing it in and make sure you can screw in the sides to your cabinet (meaning, check to see you didn't cut the hole too big). Pop in some black screws and it settles in nicely.
I also replaced the Coin Door incandescent lights with 4-LED red lights available at SuperBrightLEDs.com. The part ID is "WLED-R4 Red LED Bulb". This gives a much nicer glow than the white LEDs I bought and will last 50 times longer than the incandescent lights. They just pop in the same spot as the old lights using the same socket. If you can replace a bulb, you can do this.
Here are the Coin Door lights: