trigger assembly? 2 questions

[cloves]

ok..i have an old kraken that keeps crapping out on me. Every time I open the mechbox it would appear that the trigger contacts are burnt and black. I scuff them up with a ScotchBrite pad so they are shiny again, and the gun works like a charm.
So the first question is, why does this keep happening? I thought maybe it was a problem with all of the grease/lube in the box getting into the trigger assembly, but the gears have been essentially degreased and relubed very sparingly.
Second queston is...where can one buy a new trigger assembly? Specifically those contacts? I've looked on a few retail sites and can find lots of complete mechboxes...and shells...but the stuff inside.....i see gears,springs, cylinders etc etc etc...but not those contacts.

[Crunchmeister]

Install a MOSFET (like a Triggermaster) and the problem is solved. You won't need to replace anything else.

[Skladfin]

That is the carbon build up from trigger corrosion. It happens in all guns, V2, V3 alike. No matter what new trigger contacts you purchase, it will have that over time.

The only way to eliminate the build up is to install a MOSFET.

Hope that helps

[cloves]

interesting. i'm not sure it's worth it to instal a mosfet on a kraken though. thanks for the help

[cloves]

has anybody heard of some new JG guns coming with a mosfet of some sort already installed?

[Crunchmeister]

The new JG 416 comes with a factory mosfet. Not sure about the other models though.

[m102404]

The trigger switch of an AEG work just like one of those old throw switches that you used in science class or saw on cartoons (where a bar is essentially pushed between two live contacts to complete the circuit).

Both of those fins are live...one connects to the motor, one to the battery. When the switch block (the plastic block with the stub of metal in it) gets pushed between, it completes the circuit and the motor receives power.

Now every time the block is inserted...power arcs between the fins and the block...until a solid connection is made (then it flows through just like a solid wire). Same when the block is kicked out of position by the cut-off lever...it arcs just as it breaks connection.

So...semi-auto, where the block goes in and out for every shot, leads to more arcing than full auto.

And...big batteries (i.e. 9.6v, 11.1v, large cells, high discharge rates, etc...) will also cause more arcing.

All that arcing leave scorching/burning/corrosion/oxidization on both the fins and the block. It also "vaporises" the surface. Both of these make the situation worse and worse...and less power gets to the motor, more arcing because the contact surfaces are less and less pristine.

So...eventually you burn out your switch. You can simply pull out the old one and install a new one (typically with the whole wiring harness intact). Contact Jugglez (Airsoftparts.ca) and ask him for an AK one.

A mosfet is a circuit that "replaces" the switch. The switch is still there, but basically the mosfet acts as a gate to dump power to the motor. The MOSFET senses a very small electrical current through the switch (when you pull the trigger and push the block inbetween the fins). When it senses it, it dumps power directly from the battery to the motor. The "gate" wires don't have to carry much current...so they are typically smaller than the motor/battery wires. When the switch is disconnected, the MOSFET stops/cuts the flow of electricty to the motor. So in effect, your switch lasts forever....there's so little current/voltage going through it that doesn't burn out.

The MOSFET obviously has to be able to handle the power throughput...and turn on/off fast enough over and over so your AEG shoots properly. Just because it says MOSFET...doesn't mean that all MOSFETs are created equally. Take a look at extreme-fire.com...it's the basis of what DonP cooks up for us Canucks. Don's a good guy too...knows tons more about this stuff than I ever will.

Wordy explanation...but hey, it's lunch time.

Hope that helps,

Tys

[coach]

you could also try a dab of dielectric grease over the contacts. It won't eliminate the problem but it will decrease the amount of scorching/burning/corrosion/oxidization and prolong use before cleaning or replacing.

[cloves]

m1o24o4,
wow...thanks. so if one wanted a mosfet...i could get one from airsoftparts.ca, and donp could install?

[m102404]

I'm not sure if DonP does installations...but he certainly makes and sells one of the best MOSFETs available. The Triggermaster III is so good (check out Don's website Unconventional airsoft...it's a link under the menu News/Info, 5th one up from the bottom)....there's TONS of features in it...but even the defaults work just peachy.

Wiring it up is a snap (sometimes your burned out switch can still be used...but if it's wonky, then don't bother).

Basically there are 6 wires that connect to the unit. +ve and -ve from the battery connector go in one end. +ve and -ve go straight from the motor to the other end. One "gate" wire goes to one switch connection...the other goes to the other and on an AK, where the solder points are on the outside of the mechbox...you don't even have to crack the mechbox open. Getting the wiring lengths and shrink wrap looking tidy is the fiddly part.

If you're not comfortable with doing it yourself...get a good local guy who's comfortable with running wires do do it for you. Don's always been a great help as well...there's plenty of pictures/instructions on his site.

Whether or not it's worth it for your Kraken...that's totally up to you. Even if you eventually ditch your Kraken and get another/something else/etc....you can always take the MOSFET out.

Tys