V2 Gearbox Basic Jefftron Mosfet Issues

[steve1462]

Hi guys,

 

So ive been fiddling about with my G&G CM16 MOD0 30th Anniversary that failed on me a while back. Turns out it was the trigger contacts.

 

I bought a basic Jefftron mosfet for it, which I've installed and am having a few issues - plugged in the battery and nothing happened apart from the wires and grip getting hot. Thought I had maybe got a short, checked it all out and nothing is rubbing and its wired as per the instructions.

 

left the motor out of the grip and attached the battery - and the motor spins constantly whether its in safe / semi / auto mode. What have i done wrong?

 

I am completely lost as to why it is permanently engaged like the trigger is pulled in, but its not. That also doesnt account for why its running even in safe mode.

 

Any help greatly appreciated....

 

 

[Sitting Duck]

Mod 0 is front wired, your pic is a rear wired gun

 

The unit is faulty or the blue positive supply wire to unit is shorting causing it fire

 

did you buy the internal unit pre-wired or did you solder it yourself

if you soldered it yourself - check for any shorts on blue wire at unit

 

something is up causing the unit to be permanently switched on & full auto - even in safe mode

so examine the blue wire being soldered without any short/bridging with other components etc...

[steve1462]

It was bought pre-soldered, and I bought a new stock for the gun to turn it to a rear wired setup. I was very careful to make sure none of the wires were rubbing etc when I routed them through the gearbox and have checked to make sure none of the wire is crimped / split.

 

I took the box apart thismorning and put back in the old non-mosfet board and hey presto it all works fine. Looks like the mosfet is faulty so it's being sent back for a replacement!

[Sitting Duck]

not a big fan of internal mosfets as more stuff to go wrong

but that is another story...

 

By the looks of it, the unit uses a reg std trigger trolley like a normal mechanical v switch

but with mosfet bollox just below it...

So the actual old school switch will have two tabs/contacts to either side of switch/prongs

and I assume one tab is soldered to pcb of mosfet & other is where the blue positive supply wire is

 

the unit could be faulty & you are returning it as it came pre-soldered (wise decision)

 

IF you soldered it yourself, then a likely place would be if the the two tabs became bridged

coz the switch is effectively closed or shorted across the two contacts

(or the board itself is fucked = permanently on)

 

I've seen a people very finely bridge the two contacts with a hairline of solder

which with a mosfet would maintain the short as such low current across the contacts

and gun fired the moment the battery was connected

under a normal non-mosfet build this ultra fine hairline short could likely blow like a fuse

but under a mosfet build the short would be maintained

The bridge was so friggin' fine you had to really view it close up zoomed in,

but yup it was bridged by just a tiny hairline solder trail - weird crap indeed

 

but yeah it came presoldered so sod it - return it as you are doing coz unit could be fucked like I said

[steve1462]

That's exactly the reason I bought it pre soldered, I dont mind doing small electrical work but knowing how small the boards are I didnt want to risk screwing it up myself!

 

Thanks for the help! Always appreciated