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Except...the trigger mech is overly complicated, and refuses to work with my GATE Merf 3.2 FET.

Then you havn't understood how it works.

 

Mine has a mosfet, albeit a simple one, and works perfectly.

 

 

You wire the control circuit of the mosfet to the electrical contacts in the upper reciever, you don't go anywhere near the lower reciever/trigger mech,

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Alternatively, with mosfets that use 2 signal wires you can the top contacts, take the lower contacts and tin the contact 'nubs' (they are just press fit pieces) and mod the lower contact 'box' so you have two lines that you can fit tiny bullet connectors to that connect to the signal wires.

 

IMAG0635_zpsjo1rbc5l.jpg

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That's a really odd way of doing it, every time you have to take the gun apart you'll have to play with disconnecting wires. I added a mini deans connector just by the motor so that I don't have to pull the motor tabs of every time I want to open the gun (I'll admit that is a design flaw)

 

Any time the trigger contacts are connected, the circuit is made across the contacts in the upper receiver, anywhere you'd put contacts inside the trigger mech, you should just put them in the upper receiver.

Why would you intentionally make your life harder than it needs to be?

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Well, I have a Trigger Master Fet that sits neatly above the barrel in the upper receiver, when I originally installed it I had the signal wires running to the upper trigger contacts. These would then be in contact with the lower trigger set contact bars, but as I found when I took the lower set apart, they little studs that come into contact with one another are only press fitted into holes in the contact bars. This to me seemed to be a weakness as you had 6 points where the electrical connectivity seemed to be poor - this was at least backed up by intermittent function on pulling the trigger with the mosfet installed on the upper contacts.

 

I removed the upper contacts (improving the external appearance in my opinion), tinned the trigger studs and added in those wires which are cut to a length where they allow me to open the receiver as carelessly as I want and all that will happen at worse is they'll slip apart, but it has reduced the number of bottle necks for what is only going to be something like 0.2A of current.

 

And in my opinion it's worth the 10 seconds extra 'hardship' on reassembly because one of the features the mosfet provides is smart rof e.g. semi auto runs at 100% motor speed for snappy shots (not that the L85 trigger aids this being as heavy as it is), but in full auto fire after the first cycle it drops the motor speed to a designated % such that it's within the RPM range given for the real thing.

 

And the nice thing about the ICS L85 is that realistically, so little goes wrong if I am having to open it up I've got bigger concerns than two wires :D

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Then you havn't understood how it works.

 

Mine has a mosfet, albeit a simple one, and works perfectly.

 

 

You wire the control circuit of the mosfet to the electrical contacts in the upper reciever, you don't go anywhere near the lower reciever/trigger mech,

 

 

I did that, and yet it refuses to work. I soldered the signal wires from the FET to two QD tabs for the upper trigger contacts.

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The reason to get a mosfet is that when the trigger contacts meet they can ark when you are using a higher discharge battery, this will damage and eventually melt the contacts (I've done this with 9.6 nicad batteries) the MOSFET uses a low voltage control circuit over the original contacts, and uses an electronic switch on the main voltage.

 

ICS trigger contacts spring together, given how the trigger unit works, so arking is less of an issue. I've been running 7.4v lipo for a while in my L86, I've not yet got round to installing the FET I have for it.

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Thanks. It's the first time I've started getting into understanding the insides of an AEG and I do really like the trigger contact mechanism and how it works. It's very difficult to block the trigger.

 

More on topic, here she is at the moment (from the Bulpup thread).

 

7y7lETp.jpg

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Thanks to you guys and this thread, I just picked up a second hand ARMY R85a1 for 40 quid. Hornbill RIS, flash hider and sight rail inbound, I'll get some pics up when she's done.

 

I intend to short-stroke a full steel rack 18 tooth piston by 3 teeth to prevent PME, plus taking 3 teeth off the sector. SHS hi-torque and a rewire, mosfet and deans job and I reckon it should be a good one.

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