M4 Safty not engaging

[Silent_Angel]

Now I've recently acquired a M4 with systema gearbox installed, this appeas to be a custom build based an G&P M4. And upon couple of test firing, the entire gun died. I took it out for some inspection and came to the conclusing that there are probly issues with the motor itself since it was dead silence when the trigger was pulled. With the motor repaired, and another test fire was done, this time the motor appears to be fine, but after about 4-5 rounds have gone through, the gun died. I noticed that the safety can no longer be engaged. (every time the gun dies, the safety fails to work meaning that while in safety the trigger can still be pulled).

Is this a electrical problem? someting in the relay not working?
or if any Gun Docs have seen this kind of porblem?

[Skladfin]

Safety cover is not engaging the trigger properly.

Also, the gun failure actually seems to be a problem with the switch assembly in general, not the motor.

best to take it to a gun doc.

[AngelusNex]

Probably a selector plate problem, i must be slipping around or not being moved when you change the fire selector, as it does 3 things; Disengage the cutoff lever for auto, create a current on the electrical safety (this is probably disengaging while you fire causing the problem) and push the mechanical safety that physically stops the trigger from moving.

[audi_bhoy]

I'd go with the same issue, selector plates decides if the trigger is locked or not. However, it should be able to fire even if the safety lever doesn't engage, as the connection should work on the trigger connectors.

Originally Posted by AngelusNex

Probably a selector plate problem, i must be slipping around or not being moved when you change the fire selector, as it does 3 things; Disengage the cutoff lever for auto, create a current on the electrical safety (this is probably disengaging while you fire causing the problem) and push the mechanical safety that physically stops the trigger from moving.

[Silent_Angel]

So the problem is probly in the Selector plate or the Switch Assembly(I think is the one with wires to the motor and the battery?)

[Danke]

On the other side of the safety lever there is a small plastic disc. That disc snugs into the U-shaped cutout in the selector plate. As the switch rotates the disc/U change the motion into a back and forth movement.

If the disc is over-riding the selector switch you can get have the problem you describe occur. When you go to fix it you really want to have a new selector plate and a new safety lever on hand.

[Silent_Angel]

well we tried reinstalling the mechbox, but it will work fine for a bit then the whole thing starts again. I was wondering is there any need for special gearing when your using a Systema Turbo Motor? Since I beleive this is a regular M100 Systema Complete gearbox. Me and my Uncle are take a look at this issue, and he being a far more mechanical compentent person then I am got the disasembly and the gearbox working all figured out. And our concesus were that the turbomotor is placing excess stress for going high rev and is kokcing stuff out of alignment? (for a lack of better word). I just wanted to post here for some confirmation. Basiclly we took appart the box and came to the same concluson with fellow members here, but it appeas that the box is being stubbern. Is this a problem with systema gearbox? or just V2 in general?

[-Clutch-]

If your still having the firing 4-5 shots and then absolutely nothing, it could be that you have really soft contacts. The systema gearboxes don't have the greatest switch assemblies from what I've heard.

The 2 prong design can suck if you get poor quality ones and they will take 4-5 shots and slowly bend down until you get no contact upon trigger pull. I had this problem before with an old gearbox, just replaced the switch assembly and everything was golden. Hope this helps!

For reference, its the 2 golden prongs under the selector plate contacts that i'm talking about.
http://www.airsoftparts.ca/store2/im...-set-m16a2.jpg

[Silent_Angel]

So.. nothing to do wit the motor I suppose? (mtor going too fast and knocking everything outa wack).

So from what I'm getting... through repat usage, the selector plate will eventually bend to a concave shape and will no longer be contacting the the switch assembly (which connects to the battery and the motor) and with no contact, no power to the motor and therefor the gun will not fire?

Is there a good plate to use? http://www.airsoftparts.ca/store2/in...oducts_id=1011 is this one a good quality? I'm not too well versed in different manufacture of parts.

Can someone elignten me where does the firing selector play into all this? when you select semi-semi auto, does the selector push the plate into the position? and if I should be replacing the firing selector.

[Danke]

On the other side of the safety lever there is a small plastic disc. That disc snugs into the U-shaped cutout in the selector plate. As the switch rotates the disc/U change the motion into a back and forth movement.

When the safety selector is on S the disc is forward and that pushes the selector plate forward. When the plate is forward it engages the safety switch and that blocks the trigger.

When you switch to single the disc pivots back and pulls the selector plate half way back; the weapon fires but the cut off lever will engage and only let the weapon cycle once.

When you switch to auto the disc pivots all the way to the back and pushes the selector plate fully back; the weapon will cycle till you release the trigger.

[DarkAngel]

Clutch, I dont know where you got that information.

Systema makes phenominal low resistance assemblys. Its their other shite thats dropping in quality such as piston, gears etc.

Rarely when a motor doesnt turn, is it a problem with the motor (unless your running a cansoft ICS). Anything anyone here says is speculation. Go through the movements, eliminate the possible causes. Thats the only way youll figure it out.

"If you eliminate all other causes, the last cause, no matter how improbable must be the issue."

Take an ohm meter and check your contacts. Eliminate the motor by checking for resistance while the trigger is pulled, and when it is not (on the red wire), the black wire will always be 0 ohms because its a direct connection from battery to motor. (Unless you have faulty wiring). This is how you diagnose electrical issues. If the electricals pan out, then work on physical. Install the lower receiver, the grip, mechbox pin. look down the side of your mechbox to see if the selector cam is inside the U Shaped groove. If it is, and the selector plate is moving, you can eliminate the body. If the selector plate when moved manually by hand, does not engage the safety bar (push against te safety lever) then either the arm from the safety lever is broken, your trigger is broken or has pieces chipped, missing etc or your selector plate is broken/damaged etc

Another common mistake is that people put the wrong trigger, selector plate, safety latch etc. IE. Someone puts an MP5 Gearbox in an M4 etc. That can cause issues.

Im not trying to be a dick to the guys posting, as Its a good thing to want to help other users. But saying "its probobly this" does nothing for the user. The information you received is sketchy at best. You have nothing to base your judgements off to help him with. Either the user brings the gun to a gun doc to have it fixed, or he needs to diagnose the issue himself. Hes not going to do that by being told what it "might" be. We should be helping the community in a constructive way that allows the user to attempt to resolve the issue in the best possible manner without confusion.