ICS M4 gear box problem

[Zampaja]

Hi,
I just bought an MA-56 upper gearbox for my ICS-25 RAS, the rifle is only one year old and all the other parts are original.

I fired it in both semi and full auto for about 5 min and then it stopped, it felt like something was grinding and/or the motor was spinning without touching the gears.

Opened it up and everything looks fine, so i took the gearbox out and tested it, by holding the two parts together it works just fine but when I put it back in the rifle it stops working again...

Any ideas?

Thank you!

[HaZarD SFD]

IN all honesty I dont know what your saying to be the problem.. You kind of need to be more specific of the problems your having and the noises.. as far as you have said, it sounds like its the motor not sitting correctly. Best off to wind the motor all the way in and back it out as you pull the trigger ( DO NOT HOLD IT DOWN JUST PRESS AND RELEASE QUICKLY) its for testing and once it sounds healthy then stop moving the motor and test a mag or 2

[Zampaja]

so i re-checked all the gears and the piston and they are OK, as for the motor position I tried pushing it all the way up and holding it by hand and it still doesn't fire... I'm not an expert so right now i'm lost what confuses me the most is that the gearbox works if it is outside of the rifle...

PS for the noises at first it sounded like the half-thooted gear was grinding on the piston but there's no sign of that and after i took it apart and put it back in it sounded like the motor was spinning without touching the miter gear but again no sign of broken teeth...

[HaZarD SFD]

What does the rifle do when its all assembled? Does it fire? DOes it make noise? If so what noises? Is the mechbox easy to put back in the body or is it kind of hard?

[HaZarD SFD]

When the motor is all the way in it wont fire at all.. you need to back it out a 1/4 turn each time and quickly press the trigger once each time you move the motor.. soon it will free up and should start firing.

[Zampaja]

by 1/4 turn do u mean using the screw under the motor plate?
(sorry if it sounds dumb but i'm really not familiar with this stuff)

[Zampaja]

Originally Posted by HaZarD SFD

What does the rifle do when its all assembled? Does it fire? DOes it make noise? If so what noises? Is the mechbox easy to put back in the body or is it kind of hard?

when it's assemble it won't fire just a lot of mechanical noise, mainly grinding

everything fits perfectly in the body

[HaZarD SFD]

yes the screw in the bottom plate . THe one in the center as it should be an allen key screw.. dont fire it if its still grinding.. you will damage it more.. most likely its too far out..

[mcguyver]

Motor shim still in place? They have a bad habit of falling out of position if the gun gets banged hard. They're magnetic, soi if it fell out of the guides, it will be stuck to the side of your motor.

[Kos-Mos]

Quick diagnostic guide. Tell us happens exactly and what sound (type and pitch).

1-Remove the complete upper. Try to press the trigger when everything is in place (except the upper receiver). you will be able to see if anything is moving/not working.

2-Remove the motor. Remove the brushes. Remove the endbell (the plastic plate that hold the brushes). Check for any debris that can have fallen in the motor case. That might be preventing the motor from working 100%. Also check the magnets for chips/cracks. A broken magnet loses over 80% of it's efficiency. If you are not comfortable with that, skip it.

3-Check the pinion for wear/damage. Sometimes a little grain of sand can cause one hell of a mess.

4-CAREFULLY check your gears. Again, the debris can be very small.

5-Brief us on what it is.

[Zampaja]

ok so when i first opened the rifle the lower gear was running, so it was when I tried the complete gear box outside of the body, it was actually shooting just fine but once back into the body new grinding noises (high pitch) this time coming from the motor area (sounded way faster than before)
for the motor plate screw I have a regular screw which appear to be either fake or stuck i'll try to work that out
i've opened the lower gear box, cleaned up everything and it looks OK no particular wear or broken teeth, the piston's teeth are for the most brand new, minor wear sign (looks metal instead of black) on the catch one (the first large one) and the last 2, motor runs fine I will open it up later just to be 100% sure

any ideas?

btw in doing this one of the electric connection pin to the motor broke (what a great day!) so i'll have to fix that before testing the rifle again, hopefully by the end of tomorrow...

thanks again to all of you for your time!

[N_Force]

first check the piston, see is there any broken gear at the end? if so, you should find a broken piece inside the bottom part of the gear box.

second, open the top gear box, trigger on the motor see if the bottom gear box is running normal. if there is grinding noise coming from inside the motor, possible the magetic piece has been fallen off. then replace a Japanese motor.

[Zampaja]

Originally Posted by N_Force

first check the piston, see is there any broken gear at the end? if so, you should find a broken piece inside the bottom part of the gear box.

second, open the top gear box, trigger on the motor see if the bottom gear box is running normal. if there is grinding noise coming from inside the motor, possible the magetic piece has been fallen off. then replace a Japanese motor.

as ^^^^ minor wear sign for the piston but all the teeth are in place...

did that the first time everything run fine outside the body but not once back into it...

the sound from the motor i can't tell if it is from inside it or from the gear i'll check on that...

[N_Force]

if you are sure the piston has no broken gear. then use your finger to rotate the bottom gear box to make it move. feel the gera box and the motor see if you can find out where the grinding come from. if possibe, remove the motor and use finger rotate it, see if it is smooth, or sfter you remove the motor and connect the wire back to just try to run the motor alone see if it is the problem of the motor. it was happened on my m4a1-magnetic fallen off innside the motor.

[Kos-Mos]

You have to remove the large screw from the motor plate.

That is your problem.

There should be a small disk, the size of the smallest section of the motor's endbell.

That disk is going between the motor and the plate. The small set screw that is supposed to be in place of the large screw is used to adjust the motor position.

You can get one any most hardware store, CT or hobbyshop.

Look for a M2x4mm set screw. It will work.

I am 90% certain that this is the trouble. You might not have seen the disk fall when you disassembled the gun. If you don't have it, you can make one out of the cover of a soda bottle. Just cut it to the right size (might be hard) or order a replacement.