Anyone know how to repair gun controllers on arcade machines?

[SEgamer]

Wondering if anyone knows how easy it is to repair a broken gun on an arcade machine like house of the dead or area 51 or knows common problems with them. Someone near me is selling a House of the Dead 2 machine that I'd really like to get, but they say that the first player gun is broken. Any help is appreciated.

[Oldskool]

You are just going to have to take a look at it. Check the triggers, see if they don't feel right. Does the gun not swivel back and forth properly? Is it not emitting a light, does it always miss? You are going to need to figure out the symptoms first - and go from there. It may be something you can fix and repair without replacing the gun, might have to replace the gun or a sensor inside. It also depends on the type of light gun it uses. You'll want to do some research on the web on how light guns work to understand how they function.

Or maybe they simply mean by saying that the second player gun doesnt work is that it doesn't accept coins, or the start button is broken, or??

[SEgamer]

Got to take a look at it today, and everything was in working order except for the first player gun. It had no response at all, pressed the trigger and nothing happened.

I'm guessing (and mostly hoping) that the lever microswitch for the trigger is worn out since nothing happened, but course it could be anything like a bad pcb that the guns hook up to, bad solder joint, or bad cable. The thing is only $300, so that leaves me room to buy anything needed to fix it. Now the next step is clearing out a space for it.

[jb143]

The switch should be easy to diagnose. just short it out and see if it shoots. A light gun doesn't emit light so don't worry about checking for that. It might not be getting power...find the + and ground voltages and check those. If it was the sensor it would still try to shoot but wouldn't make any hits. If the guns plug into the PCB you can try swap them to see if it's the gun or not. Also, you should try to find a service manual online that might go into a bit more detail on what voltages should be where and whatnot.

[SEgamer]

Got the machine today and after swapping parts in and out of each gun, turns out the sensor is bad. It looks like the housing that goes around it was broken, and two of the extremely tiny/fragile wires on each corner of the quad photodiode weren't there. Before I spend around $150 on another sensor, I'm wondering if 4 single photodiodes can replace the quad one. To be continued...