King Arms M4a1 - Trigger contact build up - Why?
 

Tugging on the trigger of my King Arms AEG - nothing was happening (half cycles then eventually nothing)

Went in scoped around and found insane carbon build up on my trigger contacts - but i'm only using a 7.4v Lipo 1200mah stick!

A quick clean with a toothbrush and dish soap fixed it but now im wondering why its happening and i'd hate to have it happen during a game.

What are the causes? Motor? Using a lipo period? (I thought mosfests were only needed for 11.1s!)

With a quick google search im finding King Arms contacts are some what prone to this, even with only a few game uses - and with the M4a1 to try and avoid full auto.

This is my first time experiencing anything like this.

Can this be further avoided with better quality wiring? Connectors etc??

" Only using a 7.4 " doesn't change anything. Build-up can occur with any battery, those stock 8.4 NiMH included. It *will* happen with any trigger that handles the current. The design is built so each time you release the trigger, the contacts are pulled away from one another. Current being current, it tries to maintain contact as much as it can, even trying to jump trough the air to do so. That's the cause of the buildup. That's also why SEMI auto will build carbon faster.

That's why some people around here are so "anal" about mosfet use.

Technically, you don't NEED mosfet for 11.1V. Only the trigger contact wears faster.
You don't NEED mosfet for 7.4 either. The contact wears, too, just at lower rate. How much lower? Highly depends on the motor, the trigger contact, the playing style, or just luck.

If its a lipo it will eat contacts faster no matter if 7.4 or 11.1. Period. Also whats the c rating on your 7.4? S buddy of mine has had a ka m4 for 2 years with no trigger issues what so ever. He uses 9.6 nimh.

Residue on the contacts cause them to wear faster. Better wiring and connectors will not help. If the trigger sled contact is longer, it will take longer to wear out. Better quality metal on the contacts and faster trigger pulls will help.

Since arcing only happens when you pull the trigger, semi auto spam is what kills contacts and full auto is actually better for them.

Carbon buildup due to trigger arcing will happen even if you do use a shitty 8.4v Ni-cad battery. It's not a matter of if but when if you run w/o a MOSFET.The first upgrade I do to all my AEGs is install a MOSFET. Eliminated arcing and better trigger response makes this a no brainer upgrade. Extremely high quality Polish MOSFETS can be had for cheap! http://www.wgcshop.com/wgc2008/main/...=mosfet%20gate (Just avoid the pico ones, they're not as durable as the standard ones) If you don't know how to solder, then now is a great time to learn.

Better wiring and connectors will reduce the resistance, increase the current, and actually INCREASE the contacts wear or residue (although not by very much).
But no body will switch to bad wiring/connectors for that, right? :D