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View Full Version : CA M15A4 Firing problems



1shot 1kill
04-14-2007, 09:36 PM
I was just about to go into a war when my gun broke! When I squeeze the trigger a loud high pitched "ZZZZZZ" noise comes into play! It wont shoot anything. I recently went to the airsoft store for a previous problem and they changed out the gears to smaller ones. Could this be a problem? Please help me out

Bear
04-14-2007, 10:17 PM
Sounds like either the motor backed out or a piston/gear stripped. Of course those theories are based on my limited experience with mechbox internals.

HammerHead
04-14-2007, 10:22 PM
Without examining it in person, I'd say your motor no longer meshes properly with the bevel gear. I would suggest that you politely ask an experienced player to look at your replica at a skirmish. If he/she can determine that the problem is motor depth it can be readily corrected at the field.

He/she may find, however, that the problem requires a more detailed review and will share with you the options available for correction.

If you would like to correct the matter yourself, you should do some research on Google for "aeg motor depth" or "aeg motor meshing" or some variation thereof.

1shot 1kill
04-14-2007, 11:47 PM
Do you think I can adjust the screw located at the bottom of my pistol grip? To change where the motor is placed?

txsniper
04-15-2007, 12:48 AM
Go to the CA site > http://www.classicarmy.com/index.jsp Click “English” 2 times, then on the right side, look for “Spare Parts”, then click on “Gears” (give it time to load the page). There is quiet of a selection of Gears & Gear Sets. It’s possible that your Gears are mismatched or not shimmed properly for good tooth contact. Sounds like the Pinion Gear is not mated to the Bevel Gear. There may also be dirt, etc. between the Gears and caused the problem, stripped Gears. The Motor needs to be properly installed as well, nice and tight. Return the Gun to where to it was serviced; ask for them to check it for you. It is possible to run a “Pattern” on the Gears to confirm proper Tooth contact, that’s where the Shims come in. The Bushings or Bearings also need to be in good shape as well as proper mating of the Gearbox. Hope this helps!

1shot 1kill
04-15-2007, 01:05 AM
There is gonna be a big game on Saturday the 21st, and last time I went to the place I got my gun back in four weeks just so they can replace the gears. It's the only store thats even close to where I live. Do you think I would have better luck sending it to airsoft gi? When I order stuff I get it in 3 days! And can you explain to me what they do when they run a "pattern"

AustinWolv
04-15-2007, 02:20 AM
The Motor needs to be properly installed as well, nice and tight.
Actually in M16 series AEGs, the motor needs to free-float. If it is installed so that it is tight and won't move, i.e. jammed into place because the wiring isn't routed correctly, bad things happen.


Do you think I can adjust the screw located at the bottom of my pistol grip? To change where the motor is placed?
Yes, I think you *can*. That doesn't mean I think you should until someone else with experience takes a look at it.

they changed out the gears to smaller ones
Explain. That is not an accurate possibility, unless you mean lower-torque, not physical size.


I went to the place I got my gun back in four weeks just so they can replace the gears
What "place"? It should take all of a couple hours to rebuild your mechbox at most. However, it depends on their work queue.

Do you think I would have better luck sending it to airsoft gi? When I order stuff I get it in 3 days
Ordering parts is different than getting repair work done. Don't expect the same type of turnaround.

If you want your gun fixed quickly, you'll find a local experienced player to help you.

1shot 1kill
04-15-2007, 11:30 AM
AustinWolv, The store was Jungle Toy and they said with the previous problem was that the gears were rubbing up against the bottom of the mechbox so he replaced them with smaller ones. (If you remmember from my previous thread when I kept blowing fuses)

AustinWolv
04-15-2007, 07:19 PM
Sounds like bunk to me. I can't say I've seen that happen in any gun that I've worked on/seen (assuming "bottom" means towards where the motor mounts if the mechbox is stood up vertically like when it is mounted in the gun).

txsniper
04-16-2007, 06:34 AM
I agree with AustinWolv on this part. Seem’s like the Repair(s) just are not being handled properly. Without seeing the mechbox, it is going to be hard to diagnose here. As far as the “Pattern”, check the following link, it’s the best I could find at the moment. Regardless of the application, size, or equipment, the principal is the same. Horrible looking Gears! You are verifying where the Gear Teeth make contact with each other. Scroll down the page…
http://www.gearinstalls.com/kyron.htm See the Yellow stuff on the Gears? Years ago, Mechanics used “White Lead”. When that was discontinued, Mechanics started to use Carpenter’s “Line Chalk” (Yellow works the best). It’ can be found at most Hardware Stores, add several drops of light oil to about a Teaspoon of Chalk and make a Paste. It is then put on the Ring Gear & Pinion to see the “Contact Pattern” between the Teeth of the Gears. It may sound a little far fetched, but sometime you have to do what you have to do. This will tell you where the Teeth are touching Gear to Gear. When problem is resolved, clean all Gears before final assembly.
With that ZZZZZZZ sound, I bet you are going to need a Bevel and Pinion Gear, at the least. My opinion would be to replace ALL Gears with a new set of Stock Gears, they all make Tooth contact with each other.
I still say the Motor has to be in a fixed position. The Pinion Gear must be held securely against the Bevel Gear. The Motor can’t “Float”. Also, I don’t remember saying anything about “jamming any wires”?? There may be a Shim or Washer between the base of the Motor and the Grip Base, is it there? Also, check those Gear Bushings and confirm Shim’s are on All Gears, as required. If a Shim is missing under or on top of a Gear, one Gear may be jumping over the other Gear(s).
Check the “FAQ” section on the LSA Site > http://www.lonestarairsoft.com/forums/faq.php?faq=new_faq_item#faq_lsa_faq_item0
Scroll down to “AEG Upgrading” and then click on “How do I learn about my mechbox”, watch the Video’s. It may not be exactly what you have, but Great information anyway.

AustinWolv
04-16-2007, 08:32 AM
I still say the Motor has to be in a fixed position. The Pinion Gear must be held securely against the Bevel Gear. The Motor can’t “Float”.
The motor in the M-series must float in the grip. Then, a small washer is placed on the motor endbell which a set screw in the grip endplate pushes on when that endplate is installed. That set screw pushes on the washer which of course pushes on the motor, which in turn has the spring on the motor shaft to provide resistance against that set screw. That sets how far the motor protrudes into the mechbox, so that the pinion and bevel gear have a proper mesh.
So yes, as an assembly, the motor is held to a fixed location by the set screw. As a correct installation, the motor floats and must be able to spring up and down.

Also, I don’t remember saying anything about “jamming any wires”?? I didn't say you did. It was mentioned because that is a common problem in which people don't route the wires correctly, the motor is jammed into the grip instead of being allowed to float, and then the gears are jammed together, etc.

1shot 1kill
04-16-2007, 06:25 PM
Ok, I called the guy and he new immediatly that it was a stripped piston. And he said he will get it fixed before the Saturday that I have 2 airsoft games so I think I am gonna be good. And yes AustinWolv I do mean that.