Malfunctioning Gearbox

[Decho]

I have a G&G plastica M16A2 (labelled as a GR16A2), which, as became apparent last Saturday, has developed a fault. Specifically, I believe that something is jamming up, as when the trigger is pulled there is no action, though the wiring does get hot.

I've taken it apart, the anti-reversal latch is fine, as are, as far as I can see, all of the components. The gears function as expected, the shimming is to the best I can determine acceptable (first AEG, experience level with this kind of thing is low), everything is well lubricated, no teeth are missing and the motor turns when not attached to the gearbox as one would expect.

I really don't understand why it doesn't work, especially as the fault wasn't brought on by anything - I've used it successfully at one skirmish, put it away, then two weeks later took it out and suddenly there's no joy. Anyone got any advice? (I can post images of the internals tomorrow if so desired, too dark now, and my lighting leaves much to be desired)

[Genista]

Re: Malfunctioning Gearbox

Have you stripped it down since Saturday?

Does it fire in any mode at all?

[Decho]

Re: Malfunctioning Gearbox

Yeah, I stripped it today, it doesn't fire in any mode, no.

[tsv2tuff]

Re: Malfunctioning Gearbox

if all looks ok in the gearbox its a electrical issue have you checked all the wiring, fuses batterys etc? when you say the trigger has no action do you mean trigger wont pull or that nothing happens when you pull it?

[Tom Andrews]

Re: Malfunctioning Gearbox

Connect motor outside of gearbox and test. If it works you can assume that its not electrical.

With the gears in place but no anti reversal latch do they still rotate?

Have you checked the piston head is still on the piston, if it comes unscrewed it can jam the piston/gears.

Replace anti reversal latch, making sure it hinges up with the spring from below the ratchet gear.

[SAS Scott]

Try motor hight , try replacing the motor or could simply be a duff battery try different batteries and make sure they are fully charged.

Sent from my godly phone using tapatalk

[Cerbo Knight]

Re: Malfunctioning Gearbox

You might have reversed the polarities on the motor, causing it to spin the wrong way?

Or the gearbox was simply locked up, and you took it apart and installed the anti reversal latch the wrong way (or the motor polarities)

Worth a check I suppose

[Decho]

Re: Malfunctioning Gearbox

The motor operates perfectly well when not connected, yes the gears turn, both with and without the anti-reversal latch in place (obviously only in one direction with it in place).

I suppose it may be the battery but I have no others to test it with, nor any spare motors.

To be absolutely sure I tried the motor in both directions, in the normal direction it just tenses, nothing happens and the wires get hot, in the reverse I hear it hit against the anti-reversal latch as I would expect, and stop.

To be clear, when I pull the trigger nothing happens, I can pull it though.

I'm pretty sure the anti-reversal latch placement is fine, I haven't explicitly checked the piston head, though I didn't notice that it wasn't in place when I stripped it, then again I've not taken one apart before, so maybe, I'll check it.

Thanks for the replies people

[tommyVega]

Re: Malfunctioning Gearbox

Did you try to remove piston and spring and assembly everything else? If the gears rotate this will exclude the top part of the gear box, and you can focus on piston/spring/cylinder.

If it still doesn't work than you know that you have a problem with the gears (maybe a gear axle not straight?)

[Decho]

Re: Malfunctioning Gearbox

The gears rotate as expected without the tappet plate, cylinder, piston or spring in place. Additionally, with the cylinder and tappet plate in place, everything functions as expected - the air nozzle can be seen moving back and forth at speed.

I can't see any glaring issues with the piston or piston head, none of the teeth have been stripped or anything. I can take some photos if you want, have found an appropriate camera now.

[Decho]

Re: Malfunctioning Gearbox

Damnable lack of edit function.

OK, I've been toying with it and it looks like it always jams when the air nozzle is as far in as it goes, not totally sure where in the cycle overall this actually comes, but still. Logically though, that means the motor is compressing the spring, so the motor and battery must be fine.

[tommyVega]

Re: Malfunctioning Gearbox

looks like something is slowing the piston down, and the motor doesn't have enough strength to compress the spring all the way down...

[Decho]

Re: Malfunctioning Gearbox

That sounds reasonable, though considering that nothing was changed in the gearbox between the times with it working and not, everything is stock and it isn't wear (only been used once), what could have caused the change/what can I do about it do you think?

Additionally, here's a picture of the gearbox immediately after opening post-testing:

[tommyVega]

Re: Malfunctioning Gearbox

I had a similar problem once, and it took me a lot of headaches to figure out what it was.
Basically one of the gears axles was slightly bent, and although the gears would rotate without piston, they would lock when the spring was compressed (about 3/4 of a cycle).

You could try to remove piston/cylinder/etc.. and shim the gears properly. Than close the gearbox and rotate the gears with your finger. In my case I noticed that at about 3/4 of every cycle there was a little bit of resistance, just noticeable but enough to lock the gearbox when the spring was in.

If this is the case, good luck in finding out which gear is bent. I replaced all 3 (I got a spare set of gears for free), but if you want to guess it's quite likely to be the sector gear.