Tm Hk416d Semi Auto Issue

[The Lord Tea]

Howdy folks. 
 

Suddenly my TM 416 has developed an odd fault and I’m wondering if anyone can help. 
Mid game, it’s stopped firing on semi auto. The selector still clicks into place but nothing happens, barring I can move the trigger fully as normal (though sometimes when I move it from safe to semi it will fire once... go figure). As I said, the trigger still moves in the semi position. Just no shot is fired. 
If I shift the lever ever so slightly towards full auto, it fires in semi normally. 
Full auto works fine. 
 

Any ideas and suggestions are greatly appreciated. I think it’s the selector plate without dismantling the bugger but seeking some second opinions. I don’t actually own the wrench to take the castle nut off the back so I can’t get the gearbox out :S (to my knowledge anyway)

Edited May 28, 2021 by The Lord Tea

[mightyjebus]

the selector plate makes a connection with the wiring loom and the cut off lever dictates is it fires semi or full auto. basically the selector plate allows current to flow and depending on its position the AEG will fire semi or full.

 

so you could have a couple of things wrong. The selector plate isn't making a good electrical connection when in Semi. this is quite common and caused by wear on the contacts inside the gearbox (not the trigger contacts but the tin plated metal on the side of the trigger contacts).

It could be the selector plate is worn but unlikely as there isn't much to wear out on a M4 style NGRS selector plate unlike the teeth on the AK style. Unless you flick between safe - semi - full like a madman and have worn the copper contact out on the selector plate.

 

if you have a multimeter take the motor out and connect the multimeter set to volts DC and select semi and see if you get a voltage reading when you pull the trigger. Do the same for full auto.

 

if you don't get a reading on semi then the contacts are probably worn. You can either replace the trigger switch assembly/fit a titan or bend out the tin parts on the side of the trigger assembly to make a good contact again

[The Lord Tea]

Thanks for the points to look at.  I don’t have a multimeter but will examine the contacts. I’ve got a castle nut wrench on the way so hopefully a takedown will help

[CR91]

I had this issue. works fine in Auto but semi it would almost misfire or not fire at all. It was my trigger unit fucked. swapped it for a mosfet and its working perfect again

Just now, CR91 said:

I had this issue. works fine in Auto but semi it would almost misfire or not fire at all. It was my trigger unit fucked. swapped it for a mosfet and its working perfect again

Mine was a TM 416D Devgru