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Compulsive Reload

P90 Auto only, won't fire semi only auto

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P90 will only fire in full auto, even in semi it fires full auto.

 

Was in semi when it happened, all of a sudden the gun started firing in auto without the trigger held down, tried switching to safe and it kept going until finally, it stopped.

 

Battery was red hot

 

Any ideas?

 

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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

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Replace the cut off lever. It's a common issue.

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17 minutes ago, cropzy said:

Replace the cut off lever. It's a common issue.

Is it the lever thats dodgy? Just tried firing it again and now it wont even fire on auto

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13 minutes ago, Compulsive Reload said:

Is it the lever thats dodgy? Just tried firing it again and now it wont even fire on auto

Normally cut off lever I recently had one unscrew itself.

 

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29 minutes ago, gasman said:

Normally cut off lever I recently had one unscrew itself.

 

Cut off lever looks fine? Although I don't know, can you tell by the video? Only thing I can say is the part that hits the contacts is angled upwards and barely touches them. 

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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.

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2 minutes ago, 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.

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. 

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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

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19 minutes ago, Adolf Hamster said:

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

 

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. :(

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22 minutes ago, 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. :(

 

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

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49 minutes ago, 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

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

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1 minute ago, 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

 

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.

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1 minute ago, 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.

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.

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1 hour ago, 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.

 

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.

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1 hour ago, 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.

Okay no worries, no local tech from what I can tell either.

 

Cheers

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

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On Fri Jun 29 2018 at 09:26, 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

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.

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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. 

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25 minutes ago, 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. 

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. 

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Posted (edited)
49 minutes ago, Compulsive Reload said:

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. 

Without taking the receiver apart I couldn't say for exact. But I am willing to bet its the plastic selector lever itself. All it does is prevent the body length bar from depressing fully to create full auto. 

Edited by Asomodai

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12 minutes ago, Asomodai said:

Without taking the receiver apart I couldn't say for exact. But I am willing to bet its the plastic selector lever itself. All it does is prevent the body length bar from depressing fully to create full auto. 

Right okay, is that easy to take apart or fix. May have some crap in the trigger from hydro dipping if that could be it. 

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1 hour ago, Compulsive Reload said:

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.

 

do you mean it'll fire semi but you have to really squeeze the trigger to get full auto?

 

there should be a second set of contacts behind the semi contact you can bend forward to tune where full auto should go.

 

 

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32 minutes ago, Adolf Hamster said:

 

do you mean it'll fire semi but you have to really squeeze the trigger to get full auto?

 

there should be a second set of contacts behind the semi contact you can bend forward to tune where full auto should go.

 

 

Yeah once I tightened the cutoff lever it fired semi, once I squeeze the trigger to the max it fires auto. 

 

It seemed to hit auto on the vid when I pushed the gearbox in via the backplate but was fine when loose.

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3 minutes ago, Compulsive Reload said:

Yeah once I tightened the cutoff lever it fired semi, once I squeeze the trigger to the max it fires auto. 

 

It seemed to hit auto on the vid when I pushed the gearbox in via the backplate but was fine when loose.

 

well if you're sure the gearbox is aligned properly then the contacts would be the next place i'd look.

 

they both need to be bent the same amount out- one's positive the other negative and the slider that's being pushed by the trigger bar bridges the 2.

 

as asmodai said the selector lever in these fn guns all it does is block you from pulling the trigger far enough to activate full auto.

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