P90 Auto only, won't fire semi only auto

Compulsive Reload

Compulsive Reload

Members
Joined
Apr 27, 2018
Messages
367
Reaction score
75
Last edited by a moderator:
Apparently it could be an issue with cut off lever, edges of the contacts inside the trigger go out wards slightly.

Honestly don't know where to start or how to correct.

Cheers

 
I have heard on the web of guns firing without trigger being pulled cant remember what caused it  but was not cutoff lever owner resorted to pulling battery before meltdown.

 
gasman said:
I have heard on the web of guns firing without trigger being pulled cant remember what caused it  but was not cutoff lever owner resorted to pulling battery before meltdown.
Click to expand...
Click to shrink...
It eventually stopped firing after it happened, plugged battery back in and now it only fires auto. Its seen very little use. Any way for sure to know if its the cutoff, don't want to buy a new one for no reason. 

 
am i the only one seeing the semi contact being bent at a 45° angle?

looks almost like the plastic holding it has melted and then it's been hit by something pushing it out of position.

afaik that contact you see that is bent if the semi auto contact, every trigger pull activates it and every cycle it gets cut off by the lever, there's then a secondary set of contacts that does full auto if you keep pulling back, what's happening is it's not making contact before being overridden by the full auto contacts.

i'd start by looking at getting a replacement trigger pack (whilst feeling grateful that not being a v2/v3 you can just swap the whole lot out real easy). then if it fires auto but not semi with the new one then replace the cutoff lever. although it does look like it might also be worn a tad as it should be cutting off that switch regardless.

as a preventative i'd also reccomment a mosfet for future prevention of burning out the contacts

 
Rogerborg said:
I'm seeing that too, but was too timid to speak up in case it's some sort of Bizarro World gearbox that's meant to do that. :(
Click to expand...
Click to shrink...


I'm going by the similarity to the f2000 box, its a similar idea albeit the trigger pack is mounted differently. But seeing as they both have the same 2 stage trigger i'm guessing they work the same way

 
Adolf Hamster said:
am i the only one seeing the semi contact being bent at a 45° angle?

looks almost like the plastic holding it has melted and then it's been hit by something pushing it out of position.

afaik that contact you see that is bent if the semi auto contact, every trigger pull activates it and every cycle it gets cut off by the lever, there's then a secondary set of contacts that does full auto if you keep pulling back, what's happening is it's not making contact before being overridden by the full auto contacts.

i'd start by looking at getting a replacement trigger pack (whilst feeling grateful that not being a v2/v3 you can just swap the whole lot out real easy). then if it fires auto but not semi with the new one then replace the cutoff lever. although it does look like it might also be worn a tad as it should be cutting off that switch regardless.

as a preventative i'd also reccomment a mosfet for future prevention of burning out the contacts
Click to expand...
Click to shrink...
Hi, the auto is working again just decided to stop, is that definitely the issue then the angled contact?

Any idea on where to get a trigger pack, etc. 

Cheers

 
Compulsive Reload said:
Hi, the auto is working again just decided to stop, is that definitely the issue then the angled contact?

Any idea on where to get a trigger pack, etc. 

Cheers
Click to expand...
Click to shrink...


It's certainly where i'd be starting to fix it.

Cant help on specifically where to buy it, but it shouldnt be too hard to find a complete unit.

The auto should be a seperate contact, hence why its still working even when semi is broken, although the same problem that burnt out the semi contact could also have burnt the full auto contacts hence the unreliability of running in full auto.

 
Adolf Hamster said:
It's certainly where i'd be starting to fix it.

Cant help on specifically where to buy it, but it shouldnt be too hard to find a complete unit.

The auto should be a seperate contact, hence why its still working even when semi is broken, although the same problem that burnt out the semi contact could also have burnt the full auto contacts hence the unreliability of running in full auto.
Click to expand...
Click to shrink...
Okay cheers, turns out its called a p90 wiring harness which contains the trigger, etc.

Just finding one in stock is the problem just seems like stores outside of uk.

Any recommendations on a mosfet or how to install, never done one before and not very mod savvy.

 
Compulsive Reload said:
Okay cheers, turns out its called a p90 wiring harness which contains the trigger, etc.

Just finding one in stock is the problem just seems like stores outside of uk.

Any recommendations on a mosfet or how to install, never done one before and not very mod savvy.
Click to expand...
Click to shrink...


the world of mosfets is it's own topic, and what i'm using for my setup might not meet with the general forum approval.

the mosfet install is a bit funky thanks to the dual contacts, basically you want to wire up the trigger wires from the mosfet to both semi and auto in parallel (so that either contact can trigger it). if you're not that confident with a soldering iron/figuring out circuits it might be better to look for a tech nearby who can do it.

 
Adolf Hamster said:
the world of mosfets is it's own topic, and what i'm using for my setup might not meet with the general forum approval.

the mosfet install is a bit funky thanks to the dual contacts, basically you want to wire up the trigger wires from the mosfet to both semi and auto in parallel (so that either contact can trigger it). if you're not that confident with a soldering iron/figuring out circuits it might be better to look for a tech nearby who can do it.
Click to expand...
Click to shrink...
Okay no worries, no local tech from what I can tell either.

Cheers

 
Put a wanted ad in the recommend a tech thread for your local area, someone might be able to help.

 
Adolf Hamster said:
am i the only one seeing the semi contact being bent at a 45° angle?

looks almost like the plastic holding it has melted and then it's been hit by something pushing it out of position.

afaik that contact you see that is bent if the semi auto contact, every trigger pull activates it and every cycle it gets cut off by the lever, there's then a secondary set of contacts that does full auto if you keep pulling back, what's happening is it's not making contact before being overridden by the full auto contacts.

i'd start by looking at getting a replacement trigger pack (whilst feeling grateful that not being a v2/v3 you can just swap the whole lot out real easy). then if it fires auto but not semi with the new one then replace the cutoff lever. although it does look like it might also be worn a tad as it should be cutting off that switch regardless.

as a preventative i'd also reccomment a mosfet for future prevention of burning out the contacts
Click to expand...
Click to shrink...
Replaced both parts fires auto fine, semi works, however if you hold down the trigger hard it still fires auto which is weird. I tried pushing the gearbox down further into the casing then semi worked properly for a few seconds then stopped which was odd.

Unsure as what to do now, semi works fine in a sense as you can fire without triggering auto but If I come to selling it, may be an issue, its almost as if its turned into an aug now.

 
Pretty sure its the selector plate. The F2000 has the same one, its only plastic so it could be bent behind where the trigger on semi rams against it, If it bends then it will go full auto. 

 
Asomodai said:
Pretty sure its the selector plate. The F2000 has the same one, its only plastic so it could be bent behind where the trigger on semi rams against it, If it bends then it will go full auto. 
Click to expand...
Click to shrink...
Heres a video


I had the backplate on but not screwed in what holds the gearbox in, when loose it fired semi. When pushed in it fired auto when held down. 

 
Last edited by a moderator:
You must log in or register to reply here.
Back
Top