um wtf?!

[gerbalfarm]

So yesterday I sold my KWA G36 to an old friend. Now I've had this gun for just about 1 1/2 years and have never had any problems with it all inreguards to functionality. Today I'm greeted to a message saying that the gun just started firing non stop outta the blue, on it's own. He says it was just leaning up in the corner when it just started to fire. he says the MOSFET is fried and almost set the gun on fire.

Thoughts? Is this even possible? Something smells funky about this situation and could use some advice.

[audi_bhoy]

Usually, uncontrolled firing is caused by some wires grounding on the metal of the gearbox, and then the current shorts the trigger, which makes the motor spin, regardless if the trigger is pulled or not. I'm not familiar with MOSFET, but I think that the fact it is fried may just be a result of overcharge because too much current went through for the time it lasted.

I might be wrong since it might be a known issue with MOSFET, I'm sure some others will tell their knowings about that!

[Rugger_can]

Ok,

Well get over there and take a look at it. What do you hate the guy or something?

Speculating on the internet is not going to solve the problem, you need to look at it for yourself before you come for advice.

Do, then come back and let us know whats going down.

[doc_pathfinders]

i have had one gun start firing during the night spontaneously on full auto..

it was an old FAMAS and i never did get to the bottom of why it happened, this was a few years ago (4+) and it's the only gun that i've ever heard it happen to (now with the exception of this one)

also, do KWA G36's come with MOSFETS? or did you upgrade it?? ( i have no experience with KWA guns..) normally AEG's don't come with a MOSFET..

i have heard that _some_ MOSFETS _can_ fail in the 'on' position, but that's usually after a heat-spike (due to firing) or due to ESD, not while just sitting there.

let us know what has happened

[gerbalfarm]

I fully intend to "get over there". This is a friend of mine and I'm going to fix the problem if it's something I'm responsible for. I'm not going to sell something to someone (friend or otherwise) and say tough shit, bad luck, your on your own. I just wanted some info on wether or not this can happen (gun firing on it's own) and what could possibly cause it, since I'm not an expert on these things. I have never read of or heard of anything like this happening before and was hoping to get some info before making my 2hr drive to his place to see whats up thats all.

[gerbalfarm]

Doc_pathfinders= No I did'nt upgrade it with a MOSFET I got this gun in trade and the previous owner had had it installed.

Also what ESD?

[doc_pathfinders]

short answer is it can,

long answer is that it's unlikely to have happened spontaneously,

it is possible that he was firing it, and it just 'ran away' due to the MOSFET frying, the guy feels bad and said it started firing by it's-self..

but everything is conjecture until it's diagnosed

EDIT: best question would be what was the quality of the MOSFET?

ESD= electrostatic discharge, very high voltage static (yes, i know that it's almost impossible but i'll give you what i know so you can decide what it may be..)

[gerbalfarm]

Thank you very much for the info. As to the quality of the MOSFET I don't know the previous owner didn't tell me. In all the time that i've had and used it I've never had any problems with the gun.

edit: I'm talking with him on MSn and and he said he had test fired it for about 30rds, than set it down to go out and before he reached the door it started to fire.

[CJay]

I've seen a MOSFET go out when the battery is left connected to itlong term like overnight persay and isn't unusual to lock up in the on position. if ur using a MOSFET always remove the battery - 99 times out of 100 it'll be fine but u could be that 1 outof 100 that kicks the can lol.