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AustinWolv
08-22-2004, 02:13 PM
I am unsure if others have seen this before, but I recently encountered a strange issue. Symptoms were that the AEG would fire once, and then nothing. No follow-up shots on semi or full-auto. No motor clicking or noise of any kind. Fuse was intact, and motor connectors were also engaged. Wiring was intact. Trigger had full movement. Battery was fully charged.

Upon opening the mechbox, I found a broken tappet plate, but that did not explain the problem. After installing a new tappet, the mechbox was reassembled and tested. Again, one shot and then nothing.

Upon breaking down the mechbox again, I noticed that the trigger switch wasn't moving properly and could rotate upwards as it would travel too far backwards due to the rearward spring force. This would cause the upper part of the actual trigger to miss engaging the bottom of the trigger switch. Thus, the trigger switch would not be pushed forward to complete the electrical circuit. Shortly thereafter, a small piece of metal was found that appeared to be broken. It did not take long to realize that it was a rib located behind the trigger switch that kept it from traveling too far backwards and thus rotated upwards.

Typical of Airsoft products, what a shame that a mechbox shell is ruined because of one tiny rib breaking, which could have been designed in a more robust manner. Currently, it does not appear that JB-Weld, which I applied the other day, will do the trick in recreating that rib.

Pictures attached:

cclark1985
08-22-2004, 06:53 PM
What kind of mechbox was it?

AustinWolv
08-22-2004, 07:17 PM
Ooops, I totally neglected to put that in there and meant to do so. It was a Progear (Systema) reinforced Ver2 mechbox.

Sam
08-22-2004, 10:49 PM
It would seem you could possibly find SOMETHING to epoxy in their to replace the rip can't you?

AustinWolv
08-23-2004, 07:18 AM
It is such a small feature in a very tight space, as the sector gear teeth spin right next to it, that it will be difficult to do. Considering JB-Weld didn't hold there, I'm not sure I want to keep bothering at attempting other adhesives and materials. I have better things to do. ;)

Tad
08-23-2004, 03:09 PM
How about a screw from the outside of the box in? Iím having the same problem with my ICS M4 so Iím assuming it is the same thing because Jesse D. pulled a small broken cylinder shape piece of metal out of my lower box. Mine will fire fine on full auto but only once in semi then you have to pull it apart and pus the trigger mechanism back into place. Once I get it apart again I will see if it is due to the same problem.

AustinWolv
09-26-2004, 08:49 PM
My first reaction would be that a screw head on the outside may prevent the mechbox from fitting into the body cleanly. It was easier to just pick up a TM shell that somebody didn't want after thinking a Progear shell would last them forever. ;)

Agrovale
09-26-2004, 10:42 PM
My first reaction would be that a screw head on the outside may prevent the mechbox from fitting into the body cleanly. It was easier to just pick up a TM shell that somebody didn't want after thinking a Progear shell would last them forever. ;)

You could use an allen screw if you don't want it protruding outside the shell. Then you would need to use plenty of loctite or super glue to make sure it stays put.

AustinWolv
09-26-2004, 11:07 PM
I have no doubt something could be rigged up......it just came down to how much effort I felt like investing. Hehe, not much. That trigger stop on the TM shell is much beefier, which I found interested.

Lightningx
09-28-2004, 02:42 PM
Easy to fix! Happened to my systema progear so i stupidly ordered a CA box without thinking what I could do. I stumbled across an idea. Simply take a small drill bit, and drill a hole through the box where the pin usually is. Then take a small screw, cut the head off of it, and use plyers to get it in the hole. Very easy to do. about 5 minutes for me and it feels VERY strong.

AustinWolv
09-28-2004, 02:50 PM
Good suggestion.

Possible, but doesn't sound that secure since you don't have threads tapped. What is to keep it from coming out? The mechbox shell metal is rather brittle, so press-fit seems unreliable.

Let us know how it holds up over time.

Lightningx
09-28-2004, 06:34 PM
Good suggestion.

Possible, but doesn't sound that secure since you don't have threads tapped. What is to keep it from coming out? The mechbox shell metal is rather brittle, so press-fit seems unreliable.

Let us know how it holds up over time.

I just put it in my friends upgraded m4 and it works good so far. I had to sand down the top to make sure the sector gear didnt touch but that was pretty easy to do with a file to. I didnt press fit it. I used the plyers and screwed it in. It was a very tight fit because I used a screw thats thread was slightly wider in diameter than the hole that I made so it was nice. To be more specific, I used an old marui gearbox screw for the piece...

JayZ28
10-22-2004, 12:42 PM
Interestingly I had this exact same problem with the stock CA mechbox in my M15A4RIS. My solution is very similar to that suggested by Lightningx. After trying JB-Weld and various other bonding agents without success, I decided to drill a small hole slightly smaller in diameter than the shaft of a small steel nail. Once done I drove the nail through the hole, cut the length down to size, and ground off the nail head on the other side so as to prevent interference with the tappet plate. The head could've probably been left on there since it was very thin and probably would've provided extra support, but as it sits now, the resulting "pin" has zero movement and has worked flawlessly for me through the last 10k rounds of my piston review.

-Jay