problems with a CA M15A4

[WRMorrison]

I bought this a week or so ago from Gearbox; it's the sportline model.  If I can't figure it out, I'll definitely take it back and have them look at it, but if it's something I might be able to fix, there's no sense in bothering them.  I'm completely new to the airsoft world, so I have no clue what the common symptoms are.  It's getting a bit frustrating though, as I haven't even been able to fire half of a standard mag through it yet....

The first time I fired it, I shot 4 or 5 rds in semi, then 2-3 10 rd bursts.  Then, it "locked-up."  I could hear the motor trying to turn, but it couldn't.  I used the included wall charger because I was too impatient to find my peak charger, so I just chalked it up to an insufficient charge.  Well, I charged the battery on my peak charger @.5A and everything seemed fine for 8-10 shots in semi, then the same problem; the motor tries to turn but can't.  I checked the battery voltage, and it's at 9.0V (8.4 mini pack), so it should have plenty of juice to fire.

Is there something in the gearbox that I could check out, or maybe a more common fix to this problem?  If the problem probably lies in the gearbox, is there another tutorial that might tell me what to look for?  I've heard of shim problems, but I have no idea what needs to be checked.  

Any thoughts?

-WRM

[devildog16]

Does the motor sound like its trying to turn but is stopped?  Did you try to make the motor spin outside of the gearbox?  You could be spinning the motor the wrong way, just redo the connectors to the other side.  NOTE: this would only be a problem if you've taken out the motor before.

[WRMorrison]

Nope, the motor has never been out of the pistol grip (never opened either).

-WRM

[devildog16]

I cant tell what the problem is from the discription and not being able to see it, you might want to take it in to Gearbox to have them look at it.

[Whiskey11]

I bought this a week or so ago from Gearbox; it's the sportline model.  If I can't figure it out, I'll definitely take it back and have them look at it, but if it's something I might be able to fix, there's no sense in bothering them.  I'm completely new to the airsoft world, so I have no clue what the common symptoms are.  It's getting a bit frustrating though, as I haven't even been able to fire half of a standard mag through it yet....

The first time I fired it, I shot 4 or 5 rds in semi, then 2-3 10 rd bursts.  Then, it "locked-up."  I could hear the motor trying to turn, but it couldn't.  I used the included wall charger because I was too impatient to find my peak charger, so I just chalked it up to an insufficient charge.  Well, I charged the battery on my peak charger @.5A and everything seemed fine for 8-10 shots in semi, then the same problem; the motor tries to turn but can't.  I checked the battery voltage, and it's at 9.0V (8.4 mini pack), so it should have plenty of juice to fire.

Is there something in the gearbox that I could check out, or maybe a more common fix to this problem?  If the problem probably lies in the gearbox, is there another tutorial that might tell me what to look for?  I've heard of shim problems, but I have no idea what needs to be checked.  

Any thoughts?

-WRM

It sounds an awefull lot like what initial reports on the CA Sportlines have said.  Replace the motor with a TM EG1000 or a "Proline" (hah) CA motor and this should hopefully disappear.  I've read probably close to 15 reviews speaking of similiar problems with their stock CA Sportlines.  New motor helped signifigantly.  Baring that the problem could be too tight of shimming in the gearbox (knowing the 12 odd CA's I've taken apart this is a possibility) and the first couple of shots from a battery are enough to turn it over a couple of times then it locks up.  I recommend reshimming the GB anyways as very few (read: None) manufacturers get shimming correct.

[WRMorrison]

Thanks for the advice.  

I took the gearbox apart and found a spot where the sector gear was lightly rubbing a piece of the box's casting, and I found small shavings (presumably from this contact) in the gear mesh.  I didn't have any shims on hand, but there didn't seem to be any slop in the stock setup (with the case halves screwed together; no piston assembly), and they all turned freely?  :?   But, I'm too new to the sport to decide what's good and what isn't.

The folks at Gearbox took it apart and didn't really find anything wrong; put it back together without changing anything and voilá, it works!  Now, it worked several times in the store, but at home it's a different story.  (Isn't it always... :lol:)  It worked fine for the first 20-30 shots at home, then the same problem surfaced again.  But, all I have to do is loosen the "motor screw" (I don't know the actual part name) about 1/4 turn then pull the trigger.  Then, screw it back to where it was before and it works again.   :?   Any looser and the motor spins freely.  Any tighter and it doesn't want to spin at all.  In the middle it works for a while and then stops....I'm stumped.  If the motor is a common issue, I may go ahead and replace it.

-WRM

[Whiskey11]

If there is no excessive slop in the gears and none of the gear faces are touching each other (except where the gear teeth mesh) then you are good to go with shimming.  The motor height shouldnt really be touched on a gun unless the gear set has changed.  If you have to back it out then back it in again to get it to work again then something is direly wrong with the motor or the gearbox.  Did you grind out that spot where it was rubbing?  Hell I would, and replace all of the grease in the GB too.  The motor is definetly a weak point.  If you dont mine unscrewing the motor height and screwing it back in every 60-100 shots then I guess it's good to go but I'd replace the motor anyways with a better one.

[WRMorrison]

Did you grind out that spot where it was rubbing?  Hell I would, and replace all of the grease in the GB too.

Yep, did all that.  I think I'll look around for the TM motor you mentioned; thanks.

-WRM