Tuesday, September 28, 2021
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Replace a V2 (Version 2) Wiring Harness

Simple Steps to Get the Juice Going Again!

Words: Jimmy Beckett
Photos: Walter Sidas

It always seems like in the heat of the action, your AEG will have an issue. Now that you’re sidelined, what do you do next? Some may kick the repair over to a local shop, sit back on the couch, drink Red Bull and watch a Ridiculousness marathon, but not this guy and I’m not going to let you either… it can all happen from your workbench. Here, I will show you how to replace your wiring harness on a V2 AEG. This goes for anyone having mechanical issues or who just wants to upgrade internals.

Diagnosing a harness issue can be difficult, so we’ll go through the checks process. A damaged switch assembly can cause a few problems such as loss in semi-automatic fire, a very long trigger pull, a runaway gun or one that just simply will not fire. Things I typically look for to diagnose this issue are as follows. First I check the fuse to be sure it is still good and intact. Next I make sure that the battery is fully charged. After that I check any connections on the gun, such as the ones to the motor; on some guns there is an inline connector in the wires for easier disassembly either in the stock or fore grip. If, after eliminating other causes and things point to your wiring harness, it’s time to get it out! We are going to fast-forward to the disassembly of the gearbox because there are so many different ways to take apart each gun. Here we have a basic an example of a gearbox similar to what you have on the workbench so let’s get started.

How To: Replace a V2 (Version 2) Wiring Harness

MISSION: Replace an AEG wire harness
WORK TIME: 30-45 minutes

• P1 small Phillips screwdriver
• P2 large Phillips screwdriver
• Flat head screwdriver
• 2mm hex to slide into the spring guide to stabilize the gearbox

• V2 plunger and wiring harness
• We used a Deepfire assembly from Raptors Airsoft

How To: Replace a V2 (Version 2) Wiring Harness
First you’re going to want to take off the bolt catch (if there is one). On this VFC brand gearbox there is. Use a small Phillips to take it off its retaining screw while being careful not to lose the small spring lying underneath. Immediately after that, remove all the screws around the gearbox shell using a P2 Phillips. These screws can also be 2mm hex or Torx type screws on other brands of gearbox.

How To: Replace a V2 (Version 2) Wiring Harness
Split the gearbox halves and remove the internal parts. Take a 2mm hex wrench and place it through the spring guide to keep it from flying out. Then use your free hand to take off the upper half of the gearbox, set it aside and then slowly take the spring out. Once that’s out of the way remove the piston, cylinder nozzle and tappet it one piece, making sure not to lose the tappet spring. Take out the gears, being sure to keep the shims on the gears in the correct place and finally, take out the anti-reversal latch and spring.

How To: Replace a V2 (Version 2) Wiring Harness
Now it’s time to identify the problem. Here are a few examples of what to look for in the way of damage. On your plunger assembly the two brass tabs can be bent apart and are not making adequate contact with the plunger itself (small moving part), the return spring on the top of the unit could be broken, the tabs could be burned to the point of disintegration or the small notch on the back side could be chewed up from the cutoff lever (no semi-auto).

How To: Replace a V2 (Version 2) Wiring Harness
Sometimes you can get lucky and simply push the two small tabs closer together, which will cause the circuit to close sooner, making for a shorter pull on the trigger. Too much and it can lock the plunger in place and the gun will fire longer than desired. Unfortunately if the unit is burned, melted or in overall poor condition, I recommend replacing it. If your wiring is in good shape like mine is, just replace this section by unsoldering the old unit, dropping the new one in and resoldering it to the old wires.

How To: Replace a V2 (Version 2) Wiring Harness
If you are adding in the new wiring harness and wires, you will need to be sure to place the wires correctly in the gearbox. Keep the wire that crosses the gap near the motor underneath the other wires. Make sure that when you place the wires in the grooves you are pushing them deeply into the grooves but be sure not to strip or damage the wires. This can cause the gun to fire on its own or damage your battery and new harness.

How To: Replace a V2 (Version 2) Wiring Harness
Be sure all parts are set securely into place and that the motor leads are in the right places. Red wire to the front and black wire to the back. Also be sure that the correct connector is on there as well, whether you use Tamiya or Deans.

How To: Replace a V2 (Version 2) Wiring Harness
You can now re-install the components of your gearbox and close it up. Be sure all shims are in the right place and everything is aligned properly. Snug up the gearbox screws and be sure to tighten the bolt catch as well.

How To: Replace a V2 (Version 2) Wiring Harness
You can test the gearbox wiring by attaching the power wire to your battery and then plugging in your motor. Be sure to hold the motor keeping the pinion gear away from hitting anything. Tap the trigger and the motor should turn over. If it does, you are ready to re-assemble your AEG. If not you need to check all connections and be sure the plunger is sliding freely in and out of the trigger tabs. If it does work then you can re-assemble the rest of your AEG and hit the field again.

Deep Fire Airsoft USA, deepfireairsoft.com
Raptors Airsoft, raptorsairsoft.com
VFC, gb-tech.com.tw