ICS MX5-P gearbox lock up.

[mafu10]

So I am looking at fixing my chum's mx5-p, I am pretty handy with fixing aeg's unless it involves shimming but this gun has me totally stumped.

It has been fine for 18 months then all of a sudden the gearbox locked up as full auto wouldn't release it. I took it apart, nice and easy being a split gearbox and got it running straight away. It was fine for about 100 rounds then same problem again. Initially I thought maybe the batteries were shot away, he's been running 9.6v 1500 nimh. I plugged in a nice fresh lipo of mine and it's made no difference, in fact the gearbox has started to jam after only a couple of shots.

When the gun is open the lower half of the box spins away fine no problems, there are no missing teeth, wobbly gears etc. There is also no damae to the piston, piston head or spring guide in the upper gearbox.

Any ideas why after 18 months suddenly the upper and lower gearbox no longer like each other? I am more than happy its not a battery issue.

Cheers guys.

[Phatvortex]

Re: ICS MX5-P gearbox lock up.

That's really quite odd considering its started happening out of the blue.

Could possibly be a cut off lever issue? Though if it happens in full auto that's not very likely.

Does it make any particular noises when it's jamming/ jammed? Is the motor trying to move the gears, if not, could point to a dodgy connection or something similar.

[mafu10]

Re: ICS MX5-P gearbox lock up.

Yeh it will happen after just a few shots now in either semi/full/3 rd burst so the cut off lever has to be ruled out really.

When it happens the motor buzzes trying to turn over, as soon as the upper and lower boxes are separated the motor spins away the gears no problem at all.

The other thing I have noticed is that normally when you put it in safe the ics spring release system automatically released the spring tension and it made a very clear noise when doing this. It's not making that noise anymore and my mate has said it hasn't for a while when the gun was working. So potentially it could be something to do with the spring tension release but I have no idea how that all works or if a fault with it could cause this jamming issue.

[deanfirst]

Re: ICS MX5-P gearbox lock up.

after the gearbox locked up, will the mosfet unit get very hot???

[sparrowhawk]

Re: ICS MX5-P gearbox lock up.

what about your tappet plate

[mafu10]

Re: ICS MX5-P gearbox lock up.

Tappet plate is fine, this is what's odd, there is no visible signs of wear or damage on any component. Very good point about the MOSFET system, it doesn't get hot but if that were faulty could that cause the problem? I dont think it works exactly like a normal MOSFET, the after market ones I use wouldn't jam the gearbox if they were fault I don't see how they could anyway - could be wrong.

[Phatvortex]

Re: ICS MX5-P gearbox lock up.

The spring release is controlled by an odd anti reversal latch. Have you checked that it's not binding, or jammed against the bevel gear or other such fun things?

Is the piston free to move in its rails, and is the spring guide bent or damaged in any way?

[carhartt123]

Open the ear box, take a picture for every part.

[Skolob]

Re: ICS MX5-P gearbox lock up.

Could just be motor/motor bushe wear (i.e. motor being a bit weak). If the gear box is spinning fine and piston movig. fine then the only thing left is sufficient power to drive the spring. That will be a function of battery power, controller board and motor.
Also make sure the timing is set up properly for the battery else it can stop in funny positions (which could exasperate a worn motor).