Electrical contacts melting plastic

[JohnnyDo]

personally I have seen another ICS ak47 with the exact same problem. far as I could tell the gun was bone stock, shim job was loose not over tight and the motor alignment was fairly good. Personally I think the problem is the switches are not working exactly right in the way of the main metal plug that makes contact with the two contacts doesn't seat against the contacts very well. This in effect causes a lower surface area between the switch contact points and the large metal plug (which is attached to the switch aseemebly that moves when you pull the trigger). This lower surface area causes a high resistance point for the current to go through and thus causes a high ammoutn of heat .. enough to melt the switch assembly.

To be honnest I have no idea why AEG manufactures don't go and use a solid stat switch assembly useing mosfets as they are far supiourior to mechanical switches currently used.

I have also noticed that people who use their guns on semi fire more then full auto experiance more switch failures/degregation in the switch contacts due to arching. This is becuase the inital ammount of power to turn on a motor is way more then what is required to keep it running. This causes more heat in the switch area and as such if you fire semi auto for hundreds of rounds in close sucession the heat just builds up until somethign melts.

Well these are my thoughts and theories and as such have no formal testing to prove them right or wrong. Take is with a grain of salt.

[Greylocks]

Originally Posted by kuchervano

Thank you for the input Greylocks.
And update for those who are following this exciting drama: 9.6V 1100 mAh battery does not heat/melt/burn the contacts with the motor turning free. The 8.4V 4300 mAh battery does. Going to Canadian Tire now to get a multimeter to measure the resistance/voltage/amperage of the circuit.
Reference fuse, my P90 has a 15A one, this had 30A; 20A sounds like a compromise?

Honestly, this is the kind of thing that may benefit from a visit to a DOC. It's hard to describe how easily a mechbox should turn, or a motor should draw, and so on.
The DOC would likely have all the tools needed to track down the problem.

Some guys dont really charge much to help other players out.

[kuchervano]

The gun was taken to a gun doctor, who discovered that the stock gears were defective and not grinding properly. A set of new CA gears, some lube, and a lovable shimming job gave this thing a new life. The contacts, even though discolored from heat damage will still serve for a while, and could eventually be replaced with a MOSFET rig.

Hurrah!