Double Eagle UMP Won't Fire

LSnK

[Insert long list of expletives here]

When I came home from work today, I found that my (idiot) brother had been messing around with my UMP. Long story short, it no longer works.

When I pull the trigger, the motor tries to turn but it can't. I can hear it moving slightly. I opened the gun by removing the pins, took out the part holding the gearbox/trigger/piston, and looking at the motor while attempting to fire confirmed my suspicions - it's jammed somehow.

I know it's not the battery because:

• I charged it five seconds before using it
• It's a new battery bought from Eirsoft
• The same thing happens with the spare one I have

So that raises some questions: what do I do? What's most likely to be wrong? Should I open the gearbox and have a look, and if so what should I look for? I've never disassembled an AEG before; in fact, this is my first one.

I've been told that the G&G UMP is magazine-compatible with the DE version and of even higher quality, so I would be willing to buy that as a replacement should this be unfixable, if it's more rugged and reliable. I'd like to hear some input on that.

iceage

Don't open the gearbox, unless you know what your doing. Wait....somebody in here who does know what they're doing with gearboxes will hopefully reply.

Be patient...;)

Masada

its a version 3 gearbox in the UMP, not really prone to locking up like the version 2 but always a possibility,.,
take the gearbox out as you discribed and get your hands one a knitting needle or something similar, use it to insert in the air nozzle on the front of the gearbox and push the piston all the way back, while holding the piston back you can pull the trigger with the battery connected, this will spin up the gears and with a bit of luck, unjam everything.,:)
also, G&G mags need a slight mod to get them to fit but the DE mags arnt all that bad anyway.,

iceage

See.....I told ya!! vtec to the rescue, nice one mate, hopefully it all works out for ya, hate to hear of a sick UMP in particular cos they're sexy, and I have one;)

Thanks again Vtec.

Mike.

LSnK

vtec wrote: »

take the gearbox out as you discribed and get your hands one a knitting needle or something similar, use it to insert in the air nozzle on the front of the gearbox and push the piston all the way back, while holding the piston back you can pull the trigger with the battery connected, this will spin up the gears and with a bit of luck, unjam everything.,:)

Thanks vtec. I followed your advice as far as possible, but unfortunately I can't push the piston back at all. It seems to be quite rigidly stuck in place.

JonAnderton

What mod is needed on G+G mags to make them fit the DE?

Masada

LSnK wrote: »

Thanks vtec. I followed your advice as far as possible, but unfortunately I can't push the piston back at all. It seems to be quite rigidly stuck in place.

Try unscrewing the motor and doing it again, remember though, your pressing against the spring so it might need a bit of "ooomph".,
you could open up the gearbox but if you dont haven any previous experience with them i wouldnt reccomend it without doing some research first,.,

JonAnderton wrote: »

What mod is needed on G+G mags to make them fit the DE?

theres these little ridges on it that need to be trimed off far as i know.,

LSnK

vtec wrote: »

Try unscrewing the motor and doing it again, remember though, your pressing against the spring so it might need a bit of "ooomph".,
you could open up the gearbox but if you dont haven any previous experience with them i wouldnt reccomend it without doing some research first,.,

No luck. I took off the motor, but it still wouldn't budge even with a very large amount of force applied.

Guess I better start researching then...

Masada

Looks like you'll have to open the gearboxs then.,
have a look on here., www.mechbox.com the UMP uses the same type of gearbox as the AKs and G36s, look for the vid of the version 3 gearbox and it'll explain everything for ya.,:)

ED E

Ohh, a broken UMP = a sad face:( I'll try to help you if I can, I bought the first one tony got in I beleive. Only problem I've had is at the gathing the bar from cocking handle to bolt cover snapped and was not repairable, so last night I fitted a small nut in and now both work independantly. Destroys the effect a little but still a sweet gun.

One thing I would reccomend buying would be a 9.6. If you remove the battery compartment cover (while you have the thing apart) it'll fit. Sticks out the back a slight bit when the stock is folded but its worth it for the ROF.

Mags, DE work grand. I have 2 Hi's now(530rnd) and have stuck them together with tape an a foam spacer to make it an uber spray killing machine. Also got an ACOG sight.

Anyways, on you your problem. Unfortunately I've never needed to open the GB, just remove it to tighten the selector. On that point, you probably already know this, but the ump is childs play to dismantle. Very straightfoward and quick.

If you have the receiver out then remove both allen bolts on the base of the foregrip. Line the selecto correctly to allow the catches on the saide of the GB slide up and pull it out by pushing the trigger back and lifting. If you take off the motor from the base of the GB but leave it assembled then you can have a look inside to see if anythings shattered and also you can realease the antireversal latch.

Report back your findings please,
Simon

LSnK

Lethal_Bullet wrote: »

If you take off the motor from the base of the GB but leave it assembled then you can have a look inside to see if anythings shattered and also you can realease the antireversal latch.

I did this but I can't see anything that's broken, and it doesn't rattle or anything when shaken.

I'll have a look at the anti-reversal latch later when I get a chance.

JonAnderton

theres these little ridges on it that need to be trimed off far as i know.,

G+G mags fit my one alright, maybe a little tighter, but they fit and work perfectly... I know the STAR ones are no good because apart from the feed port being in the wrong place, it has two little lips on the sides...