I can't get my gun to work after upgrading...

[Omi-san]

TM V2 gearbox.

I changed the spring (PDI 140%) and bushings. I shimmed the gears so they can easily moved by my finger while the gearbox is closed(and screwed), but not move loosely from side to side. It seems good to me.

I put the gearbox back in the receiver and install the grip and motor. When I do a test, the motor goes "bzzz" for less then a second and then nothing happens. The battery is fully charged.

I tried reinstalling the motor many times to make sure it was bouncing inside the grip and not stuck. I changed back to the stock spring to make sure my new one wasn't faulty. I loosened all the gear by removing one shim on each of them. Nothing worked so far.

And to make things worse, I stripped one of the holes where the grip is attached to the gearbox. No idea how that happened, I didn't even force the screw in.

Any idea of what might be the problem because I can't see it.

[swatt13]

definatly motor lash. your motor is not getting inserted far enough to contact your bevel gear

[ILLusion]

Also, if you stripped your pistol grip thread, that can cause the motor to back off more than it should. That grip plate NEEDS to be tight.

If you need, I have Guarder enhanced replacement pistol grips for sale with metal nuts. Much more durable than the Marui grips.

Other than that, the only thing I can think of that's causing your problem is shimming, although it sounds like you have it right. You also have to make sure that the gears aren't crashing closely to each other. There should be about a 0.8-1mm gap between each gear.

[CDN_Stalker]

Check your fuse. Could be blown. Sounds like your shimming job is fine (testing it for semi freespin as well as it being screwed shut). At times, adding a heavier spring (especially putting in a peice of shit PDI spring) wil cause your motor to draw more current in order to compress that spring, which will end up blowing your 15A fuse. Try it with a 20A, 25A, or 30A and get back to us before you start hacking your mechbox apart again.

[commandojim]

Make sure the +and the - contacts on the
motor are on right (the motors will run backwards and cause
problems,did it once myself)

[Omi-san]

The spring is a "good PDI", kinda brownish in color and 6 1/4" long.

The 15A fuse is not blown. All red/black connectors are on the right spot. The motor gets powered, I can feel it in the grip, but it's not spinning the gears.

The stripped screw hole is the one on the gearbox where the grip is held, not the one at the bottom the grip. I had the problem before stripping it anyway.

If the motor was too far back, wouldn't I hear it spinning? I played a bit with the hex screw at the bottom of the grip, but it made no difference.

Anyway... I contacted the Montreal gun doctors, I guess I'll just leave it to them if they are still around.

[Omi-san]

Originally Posted by commandojim

Make sure the +and the - contacts on the
motor are on right (the motors will run backwards and cause
problems,did it once myself)

Is it possible that the motor has the wrong red/black marks on it?

[Ibby]

Originally Posted by Omi-san

Is it possible that the motor has the wrong red/black marks on it?

That's possible, but more likely is that your red wire is shorting out on the motor plate. Make sure there's heat shrink on the wire, right up to the end of the connector. Make sure the wire isn't bare anywhere, too long, or twisted in any way.

[swatt13]

Originally Posted by Omi-san

Is it possible that the motor has the wrong red/black marks on it?

very doubtful, i know you said you checked, but it is hard to unsure sometimes, please look again for the +/- marks correspond with the wires. but according to your description the "bzzz" noise. indicates to me the motor/pinion gear IS spinning, just not inside the mechbox. as illusion said, now that the pistol grip hole is stripped, when the motor torques up, it will flex/force a gap there, causeing loss of gear contact betyween the pinion and bevel gears, or misalignment, which could cause a jam this NEEDS to be fixed abyways. just be weld the screwhole and retap via the screw..... now that i think of it, did you ensure your anti reversal latch was seated properly as well?

[Mighty Mouse]

what kind of battery? It may not provide the motor with enough torque to turn the gears...but it should with a pdi 140 because its not that stiff.

[Omi-san]

The wires connected to the motor are fine, no shortcuts.

I'm pretty sure the anti-reversal latch was/is properly placed. I carefully studied the gearbox and everything seemed just right when I assembled it, that's why this is even more frustrating.

What kind metal is the TM stock mechbox made of? How exactly would you repair the tap?

Battery is an Intellect 8.4v 1400mah.

By the way, I'd like to strangle whoever in Japan invented the V2 mechbox. What a silly design to have the motor "floating" among wires inside the grip. Why didn't they simply had a motor case at the bottom of the mechbox where it could be secured and ajusted without the wires in the ways. Then could you simply slip the plastic grip over it.

[Naglfar]

Originally Posted by Omi-san

The wires connected to the motor are fine, no shortcuts.

I'm pretty sure the anti-reversal latch was/is properly placed. I carefully studied the gearbox and everything seemed just right when I assembled it, that's why this is even more frustrating.

What kind metal is the TM stock mechbox made of? How exactly would you repair the tap?

Battery is an Intellect 8.4v 1400mah.

By the way, I'd like to strangle whoever in Japan invented the V2 mechbox. What a silly design to have the motor "floating" among wires inside the grip. Why didn't they simply had a motor case at the bottom of the mechbox where it could be secured and ajusted without the wires in the ways. Then could you simply slip the plastic grip over it.

Like a version 3 mechbox?

[CDN_Stalker]

Red wire should pass by the gearshaft, then both wires come up the rear of the grip. The way you drew the picture, I'd say it's a safe bet yo uran the wires like you drew?

Try unscrewing the motor adjust screw. Sounding like the motor got pushed in too far when you got the plate on. When the motor is pressed too far into the mechbox, it torques but doesn't spin. Back it out a bit and let us know.

[m102404]

If you're getting desperate it might be worth trying a reassembly with everything but the spring guide, spring and piston installed. Get everything together and give it a try. It should run slick as butter. If all's good there, try the stock spring again (with piston, guide, etc...). If it works fine with a "weaker" spring, your motor may be the culprit (once an old weak motor was the source of problems for a broken AEG that I was working on).

Another thing to check while you have it disassembled is that the piston can be fully compressed. Place the spring guide upright on a solid surface, place the spring on it, place just the piston on the spring. Carefully squeeze/push the piston down taking care that the spring doesn't "bow" out to the side and slides onto the guide. The piston should be able to bottom out, if nothing is catching, binding up, etc... If you can't make it compress all the way and the coils are packed up tight (i.e. physically no room left to squeeze together), you might want to consider getting a different spring or cutting 2-3 coils off the spring.

Any, just my thoughts and things I've tried in the past. Good luck, hope you get it working soon.


BTW: There seems to be a really high ratio of post-upgrade problems involving PDI springs (vs. Sysema, Guarder, PPA,
MadBull, etc...)

EDIT: Oh yeah, make sure all your batteries are fully charged up. Seems silly to suggest it, but it made the difference for a buddy last night when he was working on his M4.

[ThunderCactus]

try it with a weaker springer