So I pick up this VS Duck Hunt real cheap from Craigslist. It had missing sound and a non-working lightgun, but the game came up,
the monitor was good, and it coined up. So first thing I do is cap the audio board and replace the sound pot and then I had fully
working sound. So the next thing I do is start to check out the gun. All wiring checked out, it was getting +5V to the electronic
board in the gun, and the optic lens was good. Next thing I do is adjust the monitor for optimum picture. At this point the gun
works "some of the time". OK, so I am one step closer. I spent hours with every color combination possible, brighter, darker, more
drive and bias, less drive and bias, more and less focus and screen on the flyback. Nothing gets the gun working 100% of the time.
So now I am looking for a replacement gun. Unfortunately a working and tested VS light seems to be rare and expensive. So I get to
thinking about the Nintendo Zapper light gun. This was used on the NES, the Nintendo home entertainment system. Furthermore, it was
used to play games like Duck Hunt, the very game I own for the arcade. I figure how different can they make the 2 guns? So the
Nintendo Zapper guns typically go for $8 or $9 with a buy it now on ebay. They made these things by the millions, so they are
plentiful and cheap. I manage to get mine for $6.10 off ebay. So I get my Nintendo Zapper light gun and open it up. First thing
I notice is the optic lens looks a little cheaper but is the exact same size. Next thing I notice is the optic board inside the
gun is very similar, but not exact.
So now I get to tracing the wires and why they are slightly different. First, on the original VS gun there are 4 wires. The brown
wire is ground, the purple wire is +5v, the blue wire is a hit and the white wire is the trigger. Now cut the end connector off
of the NES zapper gun. There are 4 wires, brown, purple, blue and white. OK thats good. I unsolder the optic board off of the VS
gun and directly solder the same color wires from the zapper gun to the VS gun. I turn on the game and give it a try. NO GO.
OK, so now I closely observe the traces on the circuit boards to figure out what is different. Turns out on the NES zapper the
white wire is +5v and the purple wire is the trigger. So I reverse the white and purple wires and solder them back to the VS gun.
For testing purposes, I solder them directly to the spindle in the handle which connects directly to the gun cord back to the
cabinet. You can see this in a picture below. I turn on the game and give it another try. OK, so this time it registers everytime
I pull the trigger and makes a gun sound, but never registers a hit.
I'm still not giving up. I look back at the optic boards again. It turns out the NES zapper has an extra transistor right before
the blue wire or "hit". I take a guess that it is either inverting the signal or making it lower, so I pull out the transistor and
solder a wire directly across the solder pads. This is also in the picture below. I turn the game back on and give it a try. BAM
POW DEAD DUCKS, DEAD DUCKS....
It works!!!! How awesome is that! An NES zapper light gun is now connected to my VS system and I am playing Duck Hunt with it.
Furthermore, it is still a Nintendo gun and not some universal knock-off. I hope this helps plenty of people out get their gun
games working. Now I have a decision to make. The official nintendo grey zapper gun looks kind of good with the cab, but the
optic boards are the same shape so I could easily swap the zapper optic board into the VS gun now that I know which wire to
solder and to remove that transistor.
In the end I decided to move the Nintendo zapper optic board into the VS light gun, partially due to the metal cable attached
to the original gun, the 360 spindle movement the cable and original gun give, and of course for originality. Please note for
anyone who does this mod in the future, the zapper optic board although similar in shape was 1 to 2 millimeters larger. It was
just enough to keep the 2 halves of the gun from closing back together perfectly. I had to shave down the optic PCB and a little
internal plastic in the VS gun to get it to fit. I have now completed the "upgrade", and both gun and game are working perfectly.
Click on images below to view image gallery