[Miki01]

It's a microswitch. Chances are the microswitch has come loose form the board so that you have to pull the trigger further to make contact with it. There comes a point where it's to loose that the pins no longer contact the board and your gun won't fire. The stock ETU has some pretty cold solder joints from the factory that need to be reflowed.

One solution is to pull the ETU unit out and see the damage and if it can be re-attached. I've done this twice to my RK74 CQB. I ended up swapping out the ETU for Lonex traditional trigger contacts and re-wiring the gun with a microFET. A standard V3 trigger is required to do this as well as a modified selector plate (G&G likes proprietary stuff). You lose the ability to switch back and forth to 3rnd burst and full-auto, as well as have a traditionally longer trigger pull, however for the sake of long-term reliability this was the path I chose to go with.

I'm not too happy with the trigger response considering the longer trigger pull before the break, but it's a price I paid for peace of mind.

I'll be re-doing my RK74 later this year or over the winter with a Gate Titan Advanced unit instead.