Jammed gearbox

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Death fighter

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Hi,

My v3 gearbox keeps jamming, I have swapped the anti reversal latch yet it still keeps jamming on every pull of the trigger?

Any help would be greatly appreciated

 
What have you done to it ??

Replaced anything else - piston maybe?

Motor could be playing up, brushes motor height too high?

Battery ????

Does it do this on both semi/auto

Bit of crap in gears causing jam

Could be loads of things to poke a guess at but some more history might help

 
Have you stripped it down and tried to spin the cogs manually without the spring in place. You should be able to pull the piston through the full cycle and the latch should work, also check all trigger springs as i had a similar prob with advice from here, needed a new spring.

 
The Spring was too powerful so I cut it down a small amount but surely that wouldn't make it jam?

That is all Iv done to the gearbox.

It still jams on every press of the trigger I release the latch and it jams again.

Thanks

 
sniperslucky said:
Have you stripped it down and tried to spin the cogs manually without the spring in place. You should be able to pull the piston through the full cycle and the latch should work, also check all trigger springs as i had a similar prob with advice from here, needed a new spring.
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The trigger springs are fine like I say it's a brand new gearbox.

Thanks

 
Sitting Duck said:
What have you done to it ??

Replaced anything else - piston maybe?

Motor could be playing up, brushes motor height too high?

Battery ????

Does it do this on both semi/auto

Bit of crap in gears causing jam

Could be loads of things to poke a guess at but some more history might help
Click to expand...
Click to shrink...
Iv checked for crap in the gears and they are fine,

The motors brand new.

I have tried the battery in other guns and it works fine.

Thanks for the help

 
Death fighter said:
The Spring was too powerful so I cut it down a small amount but surely that wouldn't make it jam?

That is all Iv done to the gearbox.

It still jams on every press of the trigger I release the latch and it jams again.

Thanks
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I'd say is the piston bottoming out at the end of the box if you changed piston

or

if spring is catching on guide or guide on piston ???

That can cause a lock-up if guide/spring doesn't slip inside piston on full compression

if you have cut the spring then you need to finish that cutting neatly - or rotate spring so cut edge is inside piston

a rough edge may not be sitting well on spring guide, slipping off center and causing a jam as it approaches full compression

that rear end of box - piston - spring guide - spring itself that is the area I would be looking at quite closely

 
I'm going to change the spring now, and I'll let you know.

Thanks for the help really appreciated

 
Sitting Duck said:
I'd say is the piston bottoming out at the end of the box if you changed piston

or

if spring is catching on guide or guide on piston ???

That can cause a lock-up if guide/spring doesn't slip inside piston on full compression

if you have cut the spring then you need to finish that cutting neatly - or rotate spring so cut edge is inside piston

a rough edge may not be sitting well on spring guide, slipping off center and causing a jam as it approaches full compression

that rear end of box - piston - spring guide - spring itself that is the area I would be looking at quite closely
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That hasn't made a difference buddy just changed the spring

 
Piston must be locking up at back or a chipped gear

Or

Shimming motor height

Gotta be something daft to lock up

If motor battery is ok then it has to be silly stuff in box

But will say I got a sluggish UAR that might have a moody motor or electric problem

I use it to test springs and she sometimes struggles on modest springs then runs fine again

Think this a switch problem coz she runs ok on auto just on semi she plays up

Another gun that needs attention but it's just a tester so that can wait

Trying to think of what stuff to check in this process of elimination but starting to run out of ideas

 
Still haven't fixed this god damn gearbox!! It literally had all new internal parts and still jams on every pull of the trigger??????

 
OK let's take it in some stages if possible.......

see first of all if the motor spins on its own when trigger is pulled

undo the motor frame cage whilst still connected and just see if motor turns ok when you pull trigger

mess about with selector plate - does this selector plate have a copper strip on it at back of switch ???

Anyway test it out in stages like above in semi/auto in case the cutoff lever is not operating correctly

or the switch requires that copper plate to touch them rear prongs of switch if fitted that is.....

Try to test the switch circuit first with motor & frame/cage removed from gearbox

see if motor spins as it should in operation......

IF motor doesn't spin correctly then wire up just the motor still out of box - just to ensure the motor spins

keep trying to stop start the motor a number of times - you can have a motor with a break on one of the windings

if this happens the motor can spin up & stop ok a few times then all of a sudden not turn at all

turn motor by hand (no power) - so it reaches another winding and she runs fine again

Direct wiring of battery to motor is RISKY but is last final check to see if electrical fault or mechanical lock up

Another option BUT ONLY FOR SENSIBLE PEOPLE TO ATTEMPT !!!!!!

Try and see if using 2.8mm spade connectors wired direct to motor as it is V3 - presume with it has motor cage

so bypass the switch/trigger stuff and see if gun cycles running a 7.4v direct to motor and connected to gearbox after the other tests !!!!

ONLY IF YOU KNOW WHAT YOU ARE DOING !!!!!

Lets get the wiring/switch stuff out of the way - if she fires on auto bypassing the trigger switch then it won't be a mechanical drive chain issue like gears or piston locking - but more likely trigger/wiring/selector plate/dead zone or other issues related to trigger/switch area

PLEASE BE CAREFUL AND IF POSSIBLE USE A FUSE & SWITCH !!!!!

anything will do almost but please be careful

That is the sort of stuff or tests I would carry out based upon what I may have understood so far

please please be very careful - proceed only if you are confident and above all on a safe workbench

(not on ya carpet/bed - apply some common sense and if not sure then seek assistance before proceeding)

Last test is very risky - but if the motor spins outside box then most likely the motor will attempt to turn the box over

if box doesn't turn over then it is likely the lock is mechanical

if box does turn over then it is likely the electrical or switch parts that are problem

If you feel/know this or that is working correctly then ffs take some pics coz I'm running out of ideas & imagination atm

get used to uploading some pics to imgur etc....

take a few of box/switch/wiring/gearbox locked up and maybe some inside too

It has to be something daft I think

 
Also - don't know if I have asked this before.....

does it completely lock up for good or does she stutter & proceed to cycle if you wiggle the selector/trigger/battery/connectors etc...

if she always locks up at same point and you have a visable port in cylinder - see if you can mark the piston or something at that same point

then investigate what may be catching at that instance with box open

give us more info and some pics perhaps will help

edit:

The Spring was too powerful so I cut it down a small amount but surely that wouldn't make it jam?

That is all Iv done to the gearbox.
It still jams on every press of the trigger I release the latch and it jams again.

Thanks
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Click to shrink...

I've also seen you have changed the spring

but it still sounds like the piston/spring is catching on spring guide

or piston is bottoming out or spring getting compressed too much - but on old spring that was working you cut coils so that wouldn't add up

if the gears spin freely by hand then that would tend to rule out chips or burrs on gears - you would feel it

so that leaves the piston/spring area where lock up might be taking place

I'm assuming the daft & obvious now - you have got the polarity correct ?

well yeah - but just trying to rule out the stupid stuff now....

 
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Sitting Duck said:
Also - don't know if I have asked this before.....

does it completely lock up for good or does she stutter & proceed to cycle if you wiggle the selector/trigger/battery/connectors etc...

if she always locks up at same point and you have a visable port in cylinder - see if you can mark the piston or something at that same point

then investigate what may be catching at that instance with box open

give us more info and some pics perhaps will help

edit:

I've also seen you have changed the spring

but it still sounds like the piston/spring is catching on spring guide

or piston is bottoming out or spring getting compressed too much - but on old spring that was working you cut coils so that wouldn't add up

if the gears spin freely by hand then that would tend to rule out chips or burrs on gears - you would feel it

so that leaves the piston/spring area where lock up might be taking place

I'm assuming the daft & obvious now - you have got the polarity correct ?

well yeah - but just trying to rule out the stupid stuff now....
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Thanks for the help,

The gears are fine checked them no scuffs or broken pieces.

The motor works fine.

Selector plate does have a copper strip.

https://i.imgur.com/LpTOp8N.jpg

https://i.imgur.com/HWEUKQq.jpg

https://i.imgur.com/iUL7Gjl.jpg

As u can see from the pictures, that is were it locks up every time

 
Death fighter said:
Selector plate does have a copper strip.
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Ahhh - now that copper strip may not be making contact with the 2 little prongs behind it on switch

slide selector to left side say and see if you can just bend or pull them 2 prongs up a bit more to ensure they touch that strip on plate

Bloody hate this ultra safety crap - not saying this deffo the problem but an area I would pay close attention to and do some tests or bypass that trigger

it "can" cause issues if that circuit doesn't complete - most v2 & v3's do away with needing a copper plate on selector

So yeah investigate that area - if she locks up - press down on selector plate to ensure contact is made and see if gun cycles better

poxy copper plates

I was wrecking my brain as to what it could be - and only other explanation would be if the piston's pick up tooth would hit the right angle area by spring guide - but there should be a gap of about 1.5mm to 2mm when placed in its runners at that point:

LpTOp8N.jpg


So yeah check the copper plate is making good sound contact all the time

if that doesn't help

then investigate further if piston's pick up tooth is hitting the edge of gearbox

The piston's initial pick up tooth - the large one at the back of piston doesn't look like a big Vampire fang to me

(I've seen some pistons with a very large thick fang but your piston doesn't seem bad at all)

But if she is locking in exact same position then maybe it is catching near there

 
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Sitting Duck said:
Ahhh - now that copper strip may not be making contact with the 2 little prongs behind it on switch

slide selector to left side say and see if you can just bend or pull them 2 prongs up a bit more to ensure they touch that strip on plate

Bloody hate this ultra safety crap - not saying this deffo the problem but an area I would pay close attention to and do some tests or bypass that trigger

it "can" cause issues if that circuit doesn't complete - most v2 & v3's do away with needing a copper plate on selector

So yeah investigate that area - if she locks up - press down on selector plate to ensure contact is made and see if gun cycles better

poxy copper plates

I was wrecking my brain as to what it could be - and only other explanation would be if the piston's pick up tooth would hit the right angle area by spring guide - but there should be a gap of about 1.5mm to 2mm when placed in its runners at that point:

LpTOp8N.jpg


So yeah check the copper plate is making good sound contact all the time

if that doesn't help

then investigate further if piston's pick up tooth is hitting the edge of gearbox

The piston's initial pick up tooth - the large one at the back of piston doesn't look like a big Vampire fang to me

(I've seen some pistons with a very large thick fang but your piston doesn't seem bad at all)

But if she is locking in exact same position then maybe it is catching near there
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I'll have a check later at both them points buddy and let you know how I get on.

Thanks for the help

 
Did all of the above and we had a WORKING gearbox!! Then realised the reverse latch Spring had came off put it back on, now the god damn things jamming in a different position now! Will try again tommorow lol

 
by the sounds of it it may be more electrical/switch/wire issue

if the piston was catching - there would be marks of it hitting or catching at back of box

(which I doubt it is tbh coz if it locks up mechanically then it is usually locked)

There might be other factors like a binding piston maybe of something replaced badly or misaligned ???

Seems like the juice isn't powering the motor from poor solid circuit/connections

you can bridge the switch " prongs " with a soldered covered staple - but this is mainly for people using a mosfet

if you are not using a mosfet then those points need to be bridged with much thicker material

I feel if you get the prongs at back of switch properly touching the copper strip it should operate effectively

other issues can be addressed as & when they arise

but if she runs by directly powering motor+box together then you know where to start investigating

 
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