Meshing Trigger Switch - Trigger "clicking" & premature disconnection

[Cr0nik]

Hello,

I think I've diagnosed a problem in my V2 AEG mechbox and I'd like to ask for any advice on how I might correct it.

Background:

I bought a used/working V2 reinforced mechbox with preinstalled internals to replace my old stock one (trigger "post of death").
I swapped out the main spring and now I'm having trigger problems.
It seems the trigger, trigger switch, and cutoff lever are not meshing properly.

Description:

The trigger contacts are disconnecting prematurely before the piston can fully cycle.
The trigger is slipping underneath the trolley, and trolley is riding up over the trigger as it is pulled.
The cutoff lever is moving with the selector plate, but neither the trigger or cutoff lever are able to hold the trigger switch closed long enough for the gun to cycle.

Pulling the trigger completes the circuit momentarily, the gun begins to cycle and then I feel the trigger "break free", losing contact with the trolley, and the trolley resets immediately.
The whole thing produces a loud "click" as the trigger slips under, the trolley snaps back over, and then another smaller "click" upon releasing the trigger, when the trigger resets and has to force itself back underneath the trolley.

I've disassembled and reassembled it a few times now and observed the above occurring.
This was with only the selector plate, cutoff lever, trigger switch, trigger, and trigger safety lever installed.

Basically the trigger trolley looks like its "rocking" or "doing the wave" instead of moving straight back and forth.

So what gives?

As far as I know they're all the same stock VFC components, and were previously meshing together fine.
I've examined the parts individually and they don't appear damaged or worn. I can only conclude I'm making some rookie mistake reassembling it all.
I've watched several hours of mechbox tutorials now I can't tell what if I'm doing anything specifically wrong.

Is there some well known or common reason for this problem?
Can I shim my way out of this?

P.S.

I should mention I read the sticky on "Semi-Auto Seizure" and I'm not sure that's the problem.
The trigger is slipping under the trolley on auto as well, without the sector gear installed, and without the cutoff lever engaged.
Unless... could this be because I'm installing the trolley with the cutoff lever in the wrong position?
On auto I can see the cut off lever "up" and disengaged from the trolley, but the trigger can't hold the circuit closed.

When I pull the trigger on auto, the cutoff lever should NOT be engaging the trolley?
and the contacts should stay closed, held together by the continuous press of the trigger... right?

[lurkingknight]

manufacturing tolerances are off on the new gearbox shell. It could be that the whole switch assembly sits higher than in the original. Try rolling the trigger trolley spring the other way so that the loop that hooks onto the trolley connects to the rest of the spring on the bottom. Sometimes that makes all the difference as the spring tends to want to lift the ass end of the trolley up off the trigger. Also maybe pry the contacts open a tiny bit so there's less resistance for the trolley. You want the trolley to kiss the contacts instead of being pinched. Once you get the trigger responding, re-evaluate the cutoff lever. It might just be time to change it and the slight out of tolerance is making it more apparent, but until you get the trigger behaving as it should, don't try to diagnose it.

[Cr0nik]

Thanks, I'll try prying the contacts open a bit more.
I already tried flipping the return spring to no effect, but maybe if the contacts are a bit wider it might work.

I'll report back later when I get a chance.

Update

No fix but I see what you're saying.

I tried swapping different combinations of cutoff levers, trigger trolleys and triggers from among my spares to see how they meshed. You're right, the tolerances of the parts are all slightly different. I managed to get it working normally on auto. On semi it will cycle once; the cutoff lever will reset the trolley but then the trigger reset fails, it gets caught under the trolley like 1mm short of a full reset, and just locks the gun completely.

I'll keep trying different combinations. It's just weird because the working combination which came installed in this new gearbox shell just isn't working anymore.

[lurkingknight]

ah the dreaded trolley float... I've had it happen on some contact housings with some mechanical triggers. Friend of mine swapped out a trigger in his src because he liked the feel of the g&p trigger better and it fucked it right up. The trolley would fire once in semi and the cutoff would bump it but it would just float on the trigger hook.

This might also happen if you've had to drill out where the trigger post was and improperly tapped a new screw in the wrong position so the trolley resets back to the wrong spot.

[Cr0nik]

Originally Posted by lurkingknight

ah the dreaded trolley float...

I figured it must have had a name.

I think I'm making progress.
I've manage to get it functioning correctly with the gearbox empty.
The trigger contacts are holding closed on auto, and on semi as well with the trolley and trigger resetting cleanly when I trip the cutoff lever.

...but when I throw in the gears, cylinder assembly & main spring the additional pressure throws off the mesh. The trigger trolley is pushed slightly out of place and the trigger is "breaking free" again on pull.

So it seems like the one thing I changed in the first place (the harder main spring) is throwing off the functional mesh that came preinstalled.

I'm noticing the trigger assembly is able to move a tiny bit if I put pressure on it. The single screw that holds the trigger housing into the gearbox shell isn't preventing a tiny bit of play in the trigger housing. Maybe its something I can shim. If the housing doesn't move, then maybe the trigger trolley will ride and reset correctly.

I'll try a sliver of electrical tape between the trigger housing and the gearbox shell. Maybe I can lock down the housing without squeezing the trolley too hard.

[lurkingknight]

these weird issues are why I insist on people not use drop in gearboxes or change gearbox shells to different brands than what came in their guns. A tiny bit of variance can cause hours if not days worth of shitstorm.

Yet people insist, and then bitch when I charge them appropriate hours. lol.

[Cr0nik]

Some progress.

I finally go the chance to sit down and work on it today.
The trigger isn't "floating" or "locking" anymore.
Auto works fine.
Semi seems to be alternating between 2 states:

a) it will fire a few times, gradually cycling less and less each time before stopping with the spring fully compressed. At this point switching to auto causes it to fire and cycle normally.
b) from that point switching back to semi causes it to fire on auto while the selector is in the semi position

Then it all repeats. Basically I get it firing on semi for like 2-3 shots, before I have to cycle to auto/semi/auto/semi firing each time.
I then get to fire 2-3 shots on semi and it all starts over.
How quickly I'm pulling the trigger doesn't seem to matter, its always like 2-3 shots on semi, whether their slowly spaced out or in rapid succession.

The fact that the gun is resetting to "sort of normal" each time is confusing.
Could this be a gear timing issue?

[lurkingknight]

what gear set, spring, motor and battery are you using?

[Cr0nik]

Internals are all from a stock VFC gun apparently, stuffed into a lonex gearbox shell.
The gears looks like their "self shimming" set. The sector gear has a delay clip on it.
The motor is unmarked, supposedly VFC stock.

The spring is mine, iirc its SP110 , new.
The battery is a 7.4 1200mah valken lipo, also new.

Would photos of all this crap help?

Edit:

I just reread the sticky on semi auto seizure, and what I'm now experiencing sort of sounds like it.
Should I try a higher voltage battery? Currently I only own a few 7.4 volts.
I'm guessing they're under powered for this stock motor working against that stronger spring.

[lurkingknight]

check to see if the piston is sliding freely inside the gearbox with nothing else in it. Close the 2 halves and see if it will fall freely when you tip it over. SA seizure usually happens when you feather the trigger or pull it faster than the gun can cycle and it's stopping somewhere mid cycle. If there's enough resistance the power supplied in semi auto from the battery is not enough to turn it over off the dead spot. It sounds like you have more mechanical resistance than normal.

[Cr0nik]

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N̶o̶w̶ ̶t̶h̶a̶t̶ ̶I̶'̶v̶e̶ ̶g̶o̶t̶ ̶i̶t̶ ̶o̶p̶e̶n̶ ̶I̶'̶l̶l̶ ̶t̶r̶y̶ ̶r̶e̶a̶s̶s̶e̶m̶b̶l̶i̶n̶g̶ ̶w̶i̶t̶h̶ ̶t̶h̶e̶ ̶l̶o̶w̶e̶r̶ ̶p̶o̶w̶e̶r̶ ̶s̶p̶r̶i̶n̶g̶ ̶i̶t̶ ̶c̶a̶m̶e̶ ̶w̶i̶t̶h̶.̶

Spoke too soon, its hitching somewhere.

Wait nvm, I might have been because I was holding the two halves together, I tried screwing it shut and the piston seems to be sliding fine.
I tried tipping it at various angles, it seems to be a bit slower right side up (as in, the guns normal orientation during use).

Update

Everything is working fine with the low power spring, safe/semi/auto.
But that doesn't really solve my problem.
I need it shooting at an outdoor velocity.

So does this seem like a "mechanical problem" or that I'm just expecting too much from the individual components?
Should I consider keeping an alternate motor/spring/battery setup for outdoor games?

Update

BATTERY FIRE.

Well, "Fire" is a bit of an exaggeration.
I left the battery sitting on my desk for an hour, came back and reconnected it to the gun.
It started smoking instantly. There was some visible splitting of the battery's wrapping.
Tossed that shit in the backyard, in a metal can on the stone patio.

Fun times.

So can that be an under powered battery problem? Low voltage battery stressed by a motor requiring higher power?

[lurkingknight]

it's possible you overdrew it when the gearbox was stuck. VFC motors aren't reputed to have a whole lot of torque but the stock spring also shoots about 400fps if you know what you're doing. If the sp110 is around 400 fps then there shouldn't really be much of a difference. Depends on the brand of spring. Both factory vfc and lonex 100s will net about 390fps with a prommy barrel.

Anecdotally I might have observed minor changes in amperage draw when changing from one spring to a stiffer spring, but that was on a neo magnet motor, even the shittiest of those will pull through what most springs have to offer. Stock ferrous motors, I never bothered to try to observe on the watt meter.

Those valken packs are probably only 10-15C with who knows what as a burst rating. They are barely powerful enough to do the job.

[Cr0nik]

It really freaked me out.
I had maybe charged and discharged that battery a total of 5 or 6 times. It was barely a month old.

I use one of those smart chargers with the voltage display and the auto shutoff/alarm feature. I had it stored with a "storage" charge, took it out this evening, and charged it to test the reassembled gearbox with the indoor spring. Every thing cycled fine, the trigger didn't stick or anything, I fired maybe 100 rounds in short bursts over 2 minutes before disconnecting the battery.

I left it sitting on my desk, came back an hour later and decided to test it again, and the SECOND i plug in the connector the thing just goes *pouf*.

So 7.4V doesn't cut it with this motor then? I was probably overdrawing it?
Maybe I should just stop using this motor all together since I don't know its power requirements.
Get a new motor and a set of batteries to go with it.

[lurkingknight]

it's not the voltage, it's the output. If you don't know what the other numbers mean on the pack, you need to educate yourself on lipos better.

[ThunderCactus]

AEG gears don't have timing.
And it doesn't really matter what you're battery is rated for, if your mechbox is stuck and you're holding the trigger down, it's effectively a dead short.
If the mechbox doesn't move with a quick pull of the trigger, don't keep pulling the trigger.

Normally, this would be clear evidence of poor shimming, but since you're using self shimming gears and apparently the piston slides fine with the shell closed, we can rule that out.
So apparently your motor doesn't seem to have enough torque to pull a 400fps spring with 18:1 gears? Very odd, considering they should pull 400fps stock. But I wouldn't rule out that battery just being a piece of shit, either.
Valken alleges that they're 20C, but since they're valken, they're also probably garbage.

Try it with a turnigy nanotech 7.4v 1200mah 25-50C battery