Constant Full Auto

[JayJay-2008]

Evening guys and girls, I have a problem!

I have re-wired a friends gun (and have done this before with complete success!) and am having all manner of problems with it! No matter what I do it fires on full auto as soon as the power is connected and a fire mode is selected.

I have checked the trigger for shorts and have yet to find anything, it seems to be returning to it's start position and there are no obvious problems that I can see! It's driving me nuts! Have any of you guys come across this before?

Can anyone suggest a fix?

I'm kinda buggered cause the gun is needed for a game on sunday!

Cheers

Jay

[jagillham]

Re: Constant Full Auto

Pictures would be good. I'd have said trigger contact not returning, but you say you have checked that.

Short circuits anywhere, a bear bit of wire touching the case maybe?

[JayJay-2008]

Re: Constant Full Auto

I'll get pics up as soon as I can, I figured that there might be a short in the case, but can't find anything!

I might try removing the trigger again, I just wanted to check that I wasn't missing anything obvious!

[JayJay-2008]

Re: Constant Full Auto

Ok peoples, Update! I've replaced all of the trigger contacts from a spare trigger that I had! (M4 trigger, didn't fit the G3!)

I now have full auto firing perfectly on command but have no semi-auto!? Edit - I probably should clarify that nothing happens, no firing at all!

Any clues? I've tried to gently bend up the contacts that touch the selector plate, but not too much! And both internal contacts are good (brand new and solid contact).

I can live with this problem far better than the previous fault, but do need to get it sorted. I'm guessing that being as full auto is working perfectly, then it's just a case of a loose or poor contact somewhere?! Very frustrating!

[Codeone]

Re: Constant Full Auto

had the same problem with my G&P turned out to be the selector plate

or could also be the cut off lever

[johnnyj]

Re: Constant Full Auto

yep so many things this could be :
cut off lever
switch block is different to the old unit
motor contacts both touching the base plate
selector plate is worn
trigger contacts are to far apart

what make is the gearbox and what make is the switch set you got ?

[JayJay-2008]

Re: Constant Full Auto

The switch set is exactly the same as the original, because it is the same one! I swapped over the contacts so that the block itself was the same! The only bit that I didn't change was the moving part of the trigger which could be a little shorter! Would that cause this problem?

[JayJay-2008]

Re: Constant Full Auto

Update: I've sussed and sorted it! Turns out that the trigger contacts were not making contact with the selector plate when semi-auto was selected. Bent them a little further round and bingo!

Worth noting for future reference as this was not an obvious problem until I marked the semi auto position on the g/box and compared the contact positions.

Thanks for all those who offered advice, it was most helpful in directing me towards the problem!