Electrical Issue

[delta76]

I'm having a problem with a G&G M4.

Recently at the end of an 8 hour game my gun suddenly stopped firing when the trigger was pulled (both on semi and auto). I figured I'd change the battery...no change. I knocked it around a bit, checked the fuse all the connectors, everything seemed fine. After some time it started working again and then stopped.

So I brought it home, full battery same issue, it will fire of two or three maybe even 15 shots and then nothing pull the trigger and nothing happens.

So I took everything apart opened up the mechbox to see if any soldering was loose or the trigger assembley was damaged, couldn't see anything wrong.

I put it back together and the same issue. I realize that Tamiya connectors are notoriously bad and I'm changing to Deans, but I swaped out the Tamiya connector for a new one and the same thing is happening again. The motor connectors are fine and there are no nicks on any wires that would indicate a short.

Today I noticed the wires on the battery heating up after a few shots so I stopped.

Any ideas as to what could be wrong?? Perhaps the trigger connectors? (although I cleaned them of any debris)

[Kos-Mos]

Trigger contacts are dirty.

You will need to use fine grit sanding paper to remove all the black carbonized crap on the contacts. (inside the two tabs and on the moving part).

Also check the selector plate/contacts for the same issue.

[delta76]

I'll take another look at those thanks

[CDN_Stalker]

I had a similar problem with a G&G M14 I was given to work on, ended up being the motor had a burned out brush inside and would cycle a few times then die.After testing it actually caught fire. G&G used shit for motors. Replaced with an EG1000 and no more problems.

Hook up the motor to the wiring, but let it freely spin, and cycle it a few times, see if you can get it to repeat the problem. If it's not that, definitely check the contacts fo the triggers, the same gun I worked on above had massive arcing damage and the tip of one of the contacts was barely holding on, had to be replaced.

[delta76]

Odd.. I've got everything apart and when I cycle the motor freely it runs fine and there is no sign of any problem electrically (i.e. the motor runs everytime I pull the trigger there is no problem with the trigger connection or battery connection when the motor is independent of the mechbox)

Could the issue be that the motor lacks the power to turn over? But then why wouldn't this happen consistently?

[delta76]

I've opened up the mechbox and the trigger connectors are fairly clean no build-up of any sort. Like I said the motor cycles fine and there are no circuit interruptions when the motor is outside of the mechbox, could this actually be a motor issue?


UPDATE:

So based on not having any circuit problems while disassembled, I re-assembled the gun and fired 20 consecutive shots on semi-auto then the trigger locked, I turned it to auto and pulled the trigger no response, back to semi-auto and the trigger was still locked as if on safe. I guess I've broken my selector plate but I can't figure out where.

[Kos-Mos]

Ah!

Your trigger unit is damaged.

This issue appends when the little carrier is getting worn down.

Re-open and check under the switch unit where the trigger grabs the little moving part.

There should be a sharp notch at the rear where the trigger is resting. When that get's worn out, the trigger can get stuck at various places and the "cart" do no return to battery properly. That cause the trigger to seem to be jammed and prevent the gun from firing AND can cause the gun to be irresponsive even if the trigger can move.

Also check the little safety lever at front to see if it spins on it's shaft.

[ujiro]

I had the same issues and it was what Kos said. V2 mechbox, and the little pin/protrusion that keeps the switch block (moving part of the switch assy) from going too far back was broken off. So, it made the trigger lock randomly, and then sometimes the trigger could move freely but wouldn't be pushing the switch block.

Unfortunately its a very annoying problem. Two options are, replace the mechbox shell, or drill a hole where the pin is supposed to be, tap it, and use a set screw.

[delta76]

Yeah I notice now that that's worn down. I'll have to get to work on that, thanks guys.