The wiring of A&K Mk43 MOSFET?

[ccyg8774]

I brought a A&K Mk43 second hand, and find out the gun have been rewired, the MOSFET is no longer connected to the circuit, and the connector for connecting the MOSFET is not there anymore.
There are 3 wires come out from the MOSFET, a thick black wire, a thin black wire and a thick red wire. How should the wires be connected to the trigger and the motor?
I guess it is same as the PicoSSR, while the MOSFET being "turned on" by connect the thin black wire to the + of the battery (red), but I am not sure. Anyone can confirm or correct that? Thanks.

[ThunderCactus]

Red goes to the triggerpost and from triggerpost to motor
Black goes to motor
Other black goes to other side of trigger

If it has a microswitch chances are the mosfet wont work due to bounce

[ccyg8774]

Originally Posted by ThunderCactus

Red goes to the triggerpost and from triggerpost to motor
Black goes to motor
Other black goes to other side of trigger

If it has a microswitch chances are the mosfet wont work due to bounce

Like this?
It don't feels right when I try to wire the battery, unless I use the third trigger post on the switch, which I have no idea about...
What do you mean by "bounce"?

[ThunderCactus]

The microswitch loses contact due to mechanical shock in the mechbox. Thats why they are the worst thing you could possibly put in a gun.
You run into partial cycling problems. Either way the majority of microswitches cant be used with mosfets.

[ccyg8774]

Originally Posted by ThunderCactus

The microswitch loses contact due to mechanical shock in the mechbox. Thats why they are the worst thing you could possibly put in a gun.
You run into partial cycling problems. Either way the majority of microswitches cant be used with mosfets.

If they loses contact... Would they have the same issue without the MOSFET?

[ThunderCactus]

They have the same issue without the mosfet, you just dont notice it

[ccyg8774]

Thanks ThunderCactus.
Guess I will just keep it the way it is. But still, thank you!

[ccyg8774]

Did some more search about micro switch in airsoft.
I think what at you were trying to say is that the bouncing of the microswitch causes problem when working with MOSFETs with active breaking?
The Extreme-fire.com uses a microswitch that have nearly no bouncing (but only rated for small current, which will be fine to control the MOSFET) to work with MOSFETs with active breaking to solve the problem.
But, if I use a very basic MOSFET (may not have to be the factory build-in one of Mk43) with no active breaking, only turning on and off, with the stock microswitch, would the problem of bouncing being unnoticeable the way it works with no MOSFET?

[ThunderCactus]

With no mosfet, yes, its fine. Otherwise there would be piles and piles of threads stating how microswitch guns are totally useless lol

Even without active braking they've caused some issues. When the mosfet detects a break in the line it cuts all power almost instantly, and turns it all back on when the trigger connection is made again. I know at least one case where this resulted in very low rpm. And it's extremely not good for the mosfet.
With active braking, obviously any break results in the motor coming to a dead stop, which is no good.

I've heard some aftermarket microswitches can be used with mosfets, probably just have much stronger springs in them, but don't have any solid references for that.

If you wanna know what I'd do, I'd just rig up a micro push button switch in front of the trigger and use that to trigger the mosfet.
microswitches in airsoft are the stupidest thing anyone has ever come up with

[ccyg8774]

Originally Posted by ThunderCactus

I've heard some aftermarket microswitches can be used with mosfets, probably just have much stronger springs in them, but don't have any solid references for that.

If you wanna know what I'd do, I'd just rig up a micro push button switch in front of the trigger and use that to trigger the mosfet.
microswitches in airsoft are the stupidest thing anyone has ever come up with

I think I got it, the bouncing causes lower than usual voltage (although only briefly) during the fire cycle and that is very bad to the MOSFET, with or without AB.
Guess I will try this http://extreme-fire.com/Micro-Switch-Bounce.pdf and a MOSFET.
This is a LMG so I want to run 11.1V on it. There will be a problem to the microswitch if it does not have a MOSFET, and there will be a different problem if it does. In longer run there will even be a problem if I just use 7.4V. The one from extreme-fire.com seems to be the best solution.

[ThunderCactus]

a microswitch is no different from regular trigger contacts in that they are just as susceptible to arcing and high amperage melting. In fact, the microswitch provides smaller contacts which means more resistance, more HEAT buildup, and less battery efficiency.

[ccyg8774]

Originally Posted by ThunderCactus

a microswitch is no different from regular trigger contacts in that they are just as susceptible to arcing and high amperage melting. In fact, the microswitch provides smaller contacts which means more resistance, more HEAT buildup, and less battery efficiency.

That's why I want to get a MOSFET, even if I have to get a specific microswitch for it.

[Kos-Mos]

People confuse Computer controlled MOSFET and MOSFET.

A "simple" MOSFET will work with any switch. You could wire one to a tape-switch from a flashlight and it would be fine.

What airsoft players refer to as a MOSFET is in fact a microcontroller with a MOSFET driver and usually one of two MOSFETs. Theses will detect a voltage drop or break and consider that the cycle is complete.

The unit in the stock A&K is very basic and will work with a micro trigger without any issue.

The PICOSSR should also work as it's just a logic gate using a MOSFET for high power application.

[ccyg8774]

Originally Posted by Kos-Mos

A "simple" MOSFET will work with any switch. You could wire one to a tape-switch from a flashlight and it would be fine.

The unit in the stock A&K is very basic and will work with a micro trigger without any issue.

The PICOSSR should also work as it's just a logic gate using a MOSFET for high power application.

That was what I initally believe, but TC seems to not agree...
Plus I don't know the correct way of wiring the stock MOSFET (the diagram I draw don't looks right). The extra set of wire goes to the box mag makes it even more confusing.
If I can't get the stock one to work again, I will use a homemade one based on the Unconventional Airsoft design, and may change to a different microswitch if I need to.

[ThunderCactus]

it's not good for any piece of electronics to have high frequency voltage spikes going through it