Mp5 problems

Cheeky vimto

Cheeky vimto

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I was at a Skirmish last night and found my gun to be really temperamental. Sometimes it would be shooting fine, other times I'd pull the trigger and the motor wouldn't even try to fire. I tried 3 different batteries.

Has anyone ever experienced this? All I can think is it could be a wiring fault or the motor packing in?any suggestions?

 
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was it mostly in semi or full auto? or a mix of both?

 
Both.

I've just done a continuity test on it and I couldn't get it to fault. Would that mean its a faulty motor?

 
when it went wrong, would it fix its self if you swapped firing modes?

how did you get it to go again?

 
I can't really fire it to get it to fault as I live in a flat. The only thing I can think is if the wires don't fail when I wiggle them on the continuity test the only other thing that moves when the battery is connected is the motor. Does that sound right?

 
To get it to go I just kept trying it by holding down the trigger. Some times it would go after a few minutes, other times I would be messing with it for about 15 minutes

 
Motor weren't moving.

I just took the motor out. Continuity tested while I spin it and it was fine, teeth were fine too.

I think you were on to something with the semi/full selector. I played around with it while continuity testing and I got it to fault. Should I attempt to have a look in it or take it to a shop? I'm not sure what's in there and I don't want springs flying everywhere

 
Just drove over an hour to go to zero one in Bournemouth, what a waste of time that was. He shot it for 5 minutes and it didn't fail, so he weren't really interested after that. He said get it to fail then call the technicians number...

 
sods law, when you need it to work it wont, when you need it to fail it wont :(

in my mind its either a fire selector problem, or a trigger component.

how old is the gun?

 
It could be burning on the trigger contacts. The contact patch is very small and takes a lot of current if the power to the motor is flowing straight through it, so it does oxidise quite quickly, especially if the gun has been used a lot. I've also had some where the brass contact has burnt half away, so reducing the contact surface even more. The fact that it happens in both semi and auto suggests a circuit problem, and the fact that it didn't happen when you took it to ZO doesn't detract from that, as moving it could have jolted the moving contact into a slightly different position, so restoring contact and allowing the gun to fire.

If it happens again, the best thing is to strip it down and split the gearbox to check the contact position and mating surfaces on the trigger switch and to check for continuity of all the wires as well, to eliminate any possible broken wiring in the gearbox.

 
Not sure how old the gun is, a friend have it me. It had an old battery in it so I bought a new battery. I'll try it again a and see if the problem continues.

It was annoying how zero one didn't even offer to hold the gun and have a look at it.

 
If you can take your motor out and have a look at the brushes and see how worn they are, I had a similar problem with mine and I replaced the contacts and it worked fine

 
Cheeky vimto said:
Not sure how old the gun is, a friend have it me. It had an old battery in it so I bought a new battery. I'll try it again a and see if the problem continues.

It was annoying how zero one didn't even offer to hold the gun and have a look at it.
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not defending zero one, but they could have your gun for a day/week/month/year and it never go wrong for them :( .

Intermittent faults are the hardest to diagnose and fix, best thing to do is unless your 100% sure exactly what it is and/or cannot live with how your gun is atm, is keep running it till it finally goes wrong, as you could spend lots of £££ only to find out its a cheap fix.

 
sp00n said:
not defending zero one, but they could have your gun for a day/week/month/year and it never go wrong for them :( .

Intermittent faults are the hardest to diagnose and fix, best thing to do is unless your 100% sure exactly what it is and/or cannot live with how your gun is atm, is keep running it till it finally goes wrong, as you could spend lots of £££ only to find out its a cheap fix.
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But surely they could of kept it and tried it for atleast half hour? I would of paid for it.

I can't play with how the gun is. I left after an hour last night as I couldn't shoot back. Might as well of ran around with a plastic knife.

 
To me it sounds like a selector problem. I had something similar with my AKS. I replaced the selector plate and it works fine. Thing is that to look at, there doesn't seem to be anything wrong with the old one! A fair while ago a common piece of advice on this forum used to be "try taking it apart and putting it back together again" - you don't necessarily spot what is wrong with it, but you do know that it has gone back together properly, and it often 'magically' does the trick.

That said, it's a version 2 gearbox and I hear they are pigs to work on. At least with a selector plate change you don't have to open the shell of the gearbox (I think, Ver 2 expert needed, cos that's how it is on V3). If it's one of those selectors which have an electrical contact on them rather than just a purely mechanical function (like an ICS AK), maybe there is oxidation and pitting on that contact. Maybe just cleaning it up with sand/emery paper would do the trick.

 
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