GFC GF25

[Sitting Duck]

1 hour ago, Samurai said:

Does it spin if you remove the pistol grip's bottom plate?

 

It could be a conventional short but on safe it doesn't fire due to prongs etc....

(well from what I can make out)

which if it was shorting on the two positive leads between motor & switch it would fire regardless of safe

 

Yes the motor plate or crushed wires but that mish mash switch, the old mosfet removed/rewired

plus the gun is safe but goes nutz on semi is pointing to short somewhere around the switch area

 

needs a priest with a testmeter to look at this I think or drown it in holy water

The trouble is when people list a fault or issue it often transpires to be something very different...

 

On 10/3/2017 at 5:39 PM, uniweekendwarrior said:

Hi all,

 

My mate dropped me off his GFC GF25, I'm guessing their version of the sr25 dmr. The fault with it being it's stuck on full auto. So I'm taking it apart and I get to the selector switch and I'm stuck. On my other rifles there is a screw on the switch to remove it. How do I remove the switch from the GFC.? 

 

Tia 

 

See - the original post might have indicated an issue with selector plate or a worn Cut Off Lever not popping the trolley in semi (as they do with worn COL's)

Now it seems like a rewire from removing a duff mosfet has caused a small evil spirit to enter the gun

Or a SHORT demon in there - ok I'll get my coat

(maybe he has a G&P Satan or Devil jet motor - OK I've got me coat on now)

[uniweekendwarrior]

It's a golden eagle high power motor. 

 

Right I will strip it back to nothing check all the wiring and let you know how I get on.

 

Cheers for the help so far 

[uniweekendwarrior]

2 hours ago, Samurai said:

Does it spin if you remove the pistol grip's bottom plate?

 

Yes

[Samurai]

13 hours ago, uniweekendwarrior said:

 

Looks intact 

The not red wire looks like there is no insulation on it. Is there?

[uniweekendwarrior]

1 minute ago, Samurai said:

The not red wire looks like there is no insulation on it. Is there?

 

There is, could probably be better though. See I didn't do the wiring so I need to check it all.

[uniweekendwarrior]

Right with the motor plugged in but not in the gearbox and attached to the battery just to see if is shorted, nothing. The motor only span when the trigger contacts were pushed together. 

[Sitting Duck]

Close the gearbox up with Trigger etc but leave spring out

The trigger could be pinched or wires squished in the box

[uniweekendwarrior]

2 hours ago, Sitting Duck said:

Close the gearbox up with Trigger etc but leave spring out

The trigger could be pinched or wires squished in the box

 

Yeah that's what I was thinking maybe the trigger didn't sit probably when I closed the gearbox and pushed the contacts together or maybe it was shorting on the box itself. 

I'm actually waiting on some grease in the post before I can resemble the gearbox again.

[Sitting Duck]

The red wire's insulation at motor looks a tiny tiny bit chewed but nowt to worry about.

The red wire is dead completely dead even if it shorts on motor plate (or should be)

so the short has to be happening with silver & red wires somewhere at switch or leading up to it.

 

This short is being stopped on safe due to the prongs not completing the circuit

but goes nutz once the copper selector plate tab makes contact in semi/auto

 

If a short took place at around the bevel leading up to switch the gun would fire in safe

somehow a bit of solder or something is touching crap it shouldn't

Them copper tabs run around the side/back of switch to finish at prongs to be bridged

There two main types of switches - no tabs and with tabs needing copper plate selector

(actually there is a third type/variation rare switch with prongs but with a link in them)

 

Somewhere at that switch area a short is taking place,

maybe a blob of solder is shorting out when the trigger gets squished slightly closed up

but short doesn't flow to motor due to prongs being open in safety

[uniweekendwarrior]

Yea I reckon your right it's around the switch somewhere. 

 

Oh quick question when I fix it my mate wants it's locked to semi. What's the best way to do this?

[Sitting Duck]

1 hour ago, uniweekendwarrior said:

 

Oh quick question when I fix it my mate wants it's locked to semi. What's the best way to do this?

 

 

Your mate will love this - with a mosfet - lol

1 - a programmable one can be set to only fire a single shot burst on full auto instead of 3, 5 round burst etc...

 

2 - a regular mosfet but with an additional switch and fully locked to semi by selector plate mod

The extra switch if/when the gun locks up - you not got auto so a hidden switch can be pressed to full auto/clear it

 

3 - a screw stopping fire selector enabling auto - but pita if it locks up, but can be removed I guess

 

4 - possible plug in burst wizard like avacado but unsure if 1 rnd burst would work 101%

kong burst wizard might do it in plug/play mode perhaps and is a mosfet if needed to hardwire it in at some point

 

think best way for a SR25 is a selector plate mod, diy 3034 with extra switch etc...  as that is what it is meant to be

[uniweekendwarrior]

Diy 3034?

[Sitting Duck]

5 minutes ago, uniweekendwarrior said:

Diy 3034?

 

http://unconventional-airsoft.com/2009/08/26/how-to-make-a-basic-mosfet-switch/

 

loads of tutorials out there - can cost about £3:50 to make

or just buy a picco ssr3 as £10 firestorm mosfets have gone it seems

 

a diy 3034 is a tank of a mosfet - bit bulky but gets $hit done for peanuts

or get a Gate pico ssr3 if you only need just one mosfet and can't be ar$ed

[uniweekendwarrior]

Awesome thank you, what about the selector plate mod?

[Sitting Duck]

16 minutes ago, uniweekendwarrior said:

what about the selector plate mod?

 

 

Careful you lose Auto for good until you buy a new selector plate

 

http://www.airsoftsociety.com/threads/how-to-semi-lock.132570/

 

Pico mosfet is perhaps easier or Nano than making just one DIY one up

(but then you will need a soldering iron anyway - so what is a bit more soldering to build your own)

 

http://www.patrolbase.co.uk/airsoft/gate-picossr-3-aeg-micro-mosfet-unit.htm#.Wdu4uVtSzIU

or

http://www.patrolbase.co.uk/airsoft/gate-nanoasr-3rd-gen-advanced-solid-state-relay-mosfet.htm#.Wdu4aVtSzIU

 

When the old mosfet blew - ^ these ^ are what the owner should have replaced it with

 

the extra switch - a cheap tiny tactile switch with wires hidden/glued inside a fixed m4 DMR stock

 

just basically a way of making it cycle on auto if it ever got stuck

return to dead zone/safe zone simply pop mag, click extra trigger inside stock/magwell if feeling clever

gun cycles on auto clearing lockup without needing to strip or try to pick AR latch etc....

 

TBH - f*ck knows why when companies make a DMR type gun they don't f*cking do this anyway

[uniweekendwarrior]

35 minutes ago, Sitting Duck said:

 

 

Careful you lose Auto for good until you buy a new selector plate

 

http://www.airsoftsociety.com/threads/how-to-semi-lock.132570/

 

Pico mosfet is perhaps easier or Nano than making just one DIY one up

(but then you will need a soldering iron anyway - so what is a bit more soldering to build your own)

 

http://www.patrolbase.co.uk/airsoft/gate-picossr-3-aeg-micro-mosfet-unit.htm#.Wdu4uVtSzIU

or

http://www.patrolbase.co.uk/airsoft/gate-nanoasr-3rd-gen-advanced-solid-state-relay-mosfet.htm#.Wdu4aVtSzIU

 

When the old mosfet blew - ^ these ^ are what the owner should have replaced it with

 

the extra switch - a cheap tiny tactile switch with wires hidden/glued inside a fixed m4 DMR stock

 

just basically a way of making it cycle on auto if it ever got stuck

return to dead zone/safe zone simply pop mag, click extra trigger inside stock/magwell if feeling clever

gun cycles on auto clearing lockup without needing to strip or try to pick AR latch etc....

 

TBH - f*ck knows why when companies make a DMR type gun they don't f*cking do this anyway

 

Thank you very much I'll put a parts list together for him to buy. 

 

If I get stuck I'll be back to pick your brains.

 

I expect they don't do it because of cost. Although it may save them money on warranty returns.

[uniweekendwarrior]

On 09/10/2017 at 6:59 PM, Sitting Duck said:

 

 

Careful you lose Auto for good until you buy a new selector plate

 

http://www.airsoftsociety.com/threads/how-to-semi-lock.132570/

 

Pico mosfet is perhaps easier or Nano than making just one DIY one up

(but then you will need a soldering iron anyway - so what is a bit more soldering to build your own)

 

http://www.patrolbase.co.uk/airsoft/gate-picossr-3-aeg-micro-mosfet-unit.htm#.Wdu4uVtSzIU

or

http://www.patrolbase.co.uk/airsoft/gate-nanoasr-3rd-gen-advanced-solid-state-relay-mosfet.htm#.Wdu4aVtSzIU

 

When the old mosfet blew - ^ these ^ are what the owner should have replaced it with

 

the extra switch - a cheap tiny tactile switch with wires hidden/glued inside a fixed m4 DMR stock

 

just basically a way of making it cycle on auto if it ever got stuck

return to dead zone/safe zone simply pop mag, click extra trigger inside stock/magwell if feeling clever

gun cycles on auto clearing lockup without needing to strip or try to pick AR latch etc....

 

TBH - f*ck knows why when companies make a DMR type gun they don't f*cking do this anyway

 

Thank you very much I'll put a parts list together for him to buy. 

 

If I get stuck I'll be back to pick your brains.

 

I expect they don't do it because of cost. Although it may save them money on warranty returns.

[uniweekendwarrior]

I'm going to smash this gun soon. Had it all back together cycled and the piston got stuck and didn't return. Why? Anyone? 

[Sitting Duck]

7 hours ago, uniweekendwarrior said:

I'm going to smash this gun soon. Had it all back together cycled and the piston got stuck and didn't return. Why? Anyone? 

 

Great these toy guns eh ???

 

The back of piston could have caught on rear window of box

The piston caught on spring guide

Bit of crap caught in gears - yup even a bit of plastic or crap can lock gears

 

With your neodym motor it will likely try its best to munch through but don't

 

You will only know by yet another strip down....

BUT one thing if spring is half cocked.....

Before you try to pop the AR latch inside the gearbox by bevel to release the spring tension....

WAIT a sec....

You have a trimmed tappet plate fin, if nozzle is fully retracted then fine

But on trimmed tappet fins it is a good idea to push nozzle back just before you release ARL

if the sector cam has passed the fin - on a trimmed fin then the when the gearbox unwinds...

The cam can smash into the underside of the trimmed fin, unable to draw back the tappet and mash stuff up more

 

Being that you have a bespoke tappet plate with that jumbo cylinder head...

You don't really want to risk busting the longer tappet plate up on releasing the ARL

So it would be wise perhaps if in any doubt to push nozzle/tappet plate back

So that when the compressed spring unwinds like hell it hopefully won't smack into the base of the trimmed fin

 

Then inspect EVERYTHING for marks/wear pointing to what/where the lockup took place

[uniweekendwarrior]

Still messed up.

Stripped of reassembled.

Put it on semi and pull the trigger. The motor just spins and spins even when you release the trigger. 

Then the piston came back and just stopped. 

 

 

[uniweekendwarrior]

When I took the case off the piston jumped back into place. I took a photo so you can see where everything was when it stopped. 

 

As you can see the gear that engaged with the piston only went half way around resulting inthe piston not releasing I'm guessing. 

[Sitting Duck]

1 hour ago, uniweekendwarrior said:

Still messed up.

Stripped of reassembled.

Put it on semi and pull the trigger. The motor just spins and spins even when you release the trigger. 

Then the piston came back and just stopped. 

 

 

 

OMFG - that is deffo not right - kill the battery asap

You still have the switch problem I see....

 

But now the motor height is out and hope that is shredding teeth on pinion/bevel

 

The video shows grip and motor & plate assembled so it is all in there inside the grip

but it isn't turning jack so motor is low or there are no teeth on the bevel gear

 

examine the motor's pinion gear for any damage

then examine the bevel gear - both sets of teeth

the bevel gear to pinion get chipped but unless there is bad wear they hold up ok

the 10 bevel teeth to spur gear - these go to bits when you have a jam or lockup, so examine those

 

The shimming/motor height needs serious checking coz something major isn't right

 

pull the piston/cylinder out, check the gears spin freely without lockups or chunks of teeth missing etc....

next check the piston moves back freely without snagging or binding

examine piston for damage to teeth

 

The Angle of Engagement hasn't been done either I see

 

Not being funny, but the box is now worse than when you started

I think you might be wise to consider sending it all of to a Tech and getting the thing fixed up properly

Ask at your local site who services their rental guns or something

 

Think it would be a wise move to just get the whole thing re-done, shimmed up, rewired with mosfet etc...

All at the same time in one sitting coz so far you are going nowhere fast if not only getting worse

[uniweekendwarrior]

46 minutes ago, Sitting Duck said:

 

OMFG - that is deffo not right - kill the battery asap

You still have the switch problem I see....

 

But now the motor height is out and hope that is shredding teeth on pinion/bevel

 

The video shows grip and motor & plate assembled so it is all in there inside the grip

but it isn't turning jack so motor is low or there are no teeth on the bevel gear

 

examine the motor's pinion gear for any damage

then examine the bevel gear - both sets of teeth

the bevel gear to pinion get chipped but unless there is bad wear they hold up ok

the 10 bevel teeth to spur gear - these go to bits when you have a jam or lockup, so examine those

 

The shimming/motor height needs serious checking coz something major isn't right

 

pull the piston/cylinder out, check the gears spin freely without lockups or chunks of teeth missing etc....

next check the piston moves back freely without snagging or binding

examine piston for damage to teeth

 

The Angle of Engagement hasn't been done either I see

 

Not being funny, but the box is now worse than when you started

I think you might be wise to consider sending it all of to a Tech and getting the thing fixed up properly

Ask at your local site who services their rental guns or something

 

Think it would be a wise move to just get the whole thing re-done, shimmed up, rewired with mosfet etc...

All at the same time in one sitting coz so far you are going nowhere fast if not only getting worse

 

I take no offence at all. As the gun didn't work to begin with my mate gave me it to learn on as when if comes to gearbox I am a total noob. 

 

It's funny you mention a tech as talking to my two main site techs at the moment getting quotes haha.

 

Also tempted to just buy a new complete gearbox and drop it in

[uniweekendwarrior]

Just checked all the gear teeth and the motor and they all look fine no chips or missing teeth.

[Sitting Duck]

TBH I'd avoid splashing too much money on a new gearbox

a proper v2.5 isn't cheap or easy to source straight away

(stuff like v2.5 tappet plates are like hens teeth but other bits are similar to v2 or longer stroke cylinders can be found etc...)

 

Somebody on Airsoft Mechanics was say even G&P has stopped doing the full stroke v2.5 gearbox now

So the only real v2.5 options might be A&K or an expensive CNC one on order

Unless somebody has got one spare or going cheap - then you may have a few mild fitment issues perhaps

 

G&G just use a normal v2 with a jumbo mofo nozzle so tbh the only thing I'd do is get that JG/GFC box fixed up properly

(and tbh pass it back or sell it on unless you have fallen in love with it)

 

Don't think it is anything major - just needs the switch trouble-shooting & then rebuilt properly shimming/AoE/spring change maybe

(as said I'd sort out the short, rewire with a 3034 mosfet or cheap Gate mosfet whilst the box is in bits)

 

Nothing steep - just a bit of time & attention to rebuild it