v2 nightmares - I hate old stock parts!
 

I got a v2 that's been kicking my ass today. It should have been a basic swap from a cracked TM box to a reinforced JG box. But I can't get it to work. This is for an M4

Had a multitude of issues with it that I swapped parts with. Spur gear missing teeth/flat teeth. Sector gear had a spur gear embedded in it. Switch assembly had no power going to motor....

Anyway, got all the parts in and it should be working but it's not. When assembled I sometimes get a single full cycle. Other times I cannot turn the selector from safe to semi, or I'll not be able to pull the trigger in semi but can in auto.

It appears that when the trigger is pulled, instead of the switch sliding straight forwards, it's goes forwards and up getting stuck and allows the trigger to freely move back and forth.

Everything else operates fine. With no power connected, I can get continuity with a multimeter in semi and auto. As soon as power is connected, the trigger fails to push the switch.

Any suggestions?

So just to be sure cuz I can't tell, is the switch block (the piece that moves when you pull the trigger) in the guides properly on the main switch assy? Or are the guides on the main switch assy that the switch block slides through screwed up at all?

not the part screwed to the shell. just the little piece that moves when the trigger engages it. trigger essentially engages it once then is able to move under the piece with out touching it. it seems to be in position but there is space which allows too much play. is there a piece missing? the switch assembly is just 2 pieces with 2 covers screwed on right?

Yeah its just the piece that slides and the piece thats mounted to the box wall. Hmm sounds weird... It does sound like something is missing, off of the trigger or the switch block.

Is your trigger post broken off? There should be a post holding the moving part of the switch so the trigger can push it.

What's weirder is that I have 2 other switch assemblies and they all look the same. the one that was originally in the cracked box was essentially new and worked when the box broke. (G&P handguard assembly)

trigger is fine. identical to the one in my M4 and for a visual, is the same as this:

http://www.airsoftparts.ca/store2/im...el-trigger.jpg

No, trigger POST. Like I said it holds the moving part of the switch in the right resting position.

I think he means the trigger post on the inside of the mechbox shell. Its a little metal bar sticking up out of the shell just to the left of where the switch block (moving part of the switch assembly) is. So that when the trigger is not pulled and the switch block is all the way to the left, it is pushed up against this little post

yes, that's there. I have to unscrew the switch to change the block.

And so the block is identical to the ones from other functioning boxes, and so is the trigger..?

yes. resting postition is not the issue, it move to the right and up and doesn't return properly. and yes, the spring is installed and when I move the block by hand, it returns properly.

Might want to take it to a gundoctor who know's what he's doing. Like you said, your gun has a bunch of problems!

Hmm.. Weird. I have one idea.. It probably wouldn't do anything but hey its worth a shot. You know how the spring is shaped like this...

o--------_

Where there are loops on both ends to go to the post that the spring attaches to on the box, and then the catch on the switch block. Well, maybe its on not.. properly so that it is pulling the switch block up a little bit when it is all the way to the right. If you switch the spring so that maybe it isn't pulling the switch block from too high up, it might resolve the issue?

No that shouldn't be an issue, any way you put that spring.

I didn't think so, as I recall putting it on both ways and neither way causing any issues. But hey, its worth a shot. This is really curious though, considering from what he says, the switch assy, switch block, and trigger are all in perfect condition (nothing broken, missing, etc), there seems to be no reason as to why this would happen. It just sounds like the guide on the main switch assy is messed up somehow so that when the switch block is all the way to the right, making contact with the other half of the actual switch on the main assembly, it gets pulled up a bit.

not my gun. less an issue of needing a gun doc vs. the parts not cooperating. it's a budget build with no labour costs. he's actually getting parts thrown in for free.

the gun has been cursed. a couple of us have put too much time into it and that's on the entire gun not just the mechbox.

I've tried different spring orientations already and does nothing. Even tried a stiffer and softer spring from different stock gun leftovers.

I just recently learned of this trigger post when it broke off and I had a world of trigger problems and jam. Basically did what your saying, pull the trigger, but no power.. ALSO check the contacts that engage with the selector plate make sure they are bent up and making a good connection, I had to bend mine up after till i got solid power flow.

BTW Im not sure if you know which post we are referring too, but its not the one that the trigger sits on, its a longer one right behind it that blocks the conductor from going back to far and hitting the gear. They are susceptible to breaking in reinforced boxes I was told after I finally figure out what happened with mine..

that would make a new switch assembly, that was working in the cracked box a month ago, and 2 other switches being messed up.

s'ok. there's a complete box that's been sourced from a teammate/friend that will just require a spring swap after.

Thanks for the help guys.

Don't give up. Do it for the sake of figuring out whats wrong! :P.

with my trusty multimeter in hand, I remembered to bend up the two contacts so that they touch the selector plate. with no battery connected, I tested between the positive motor connector and all the contacts in the box up to the battery connector.

Yes, I know which post you guys are referring to. It is there and not broken as I cannot remove the conductor piece without unscrewing the selector assembly from the shell. figure being in the way means that it is still there but it still doesn't explain the fault I'm having. Not like the conductor piece is jamming up in my gears.

yeah probably will, but I've spent too much time to day opening and closing the damn box.

This is also why I try to only work on boxes with the Modify modular kits in them. :p I will probably not spend this much time on a box with 90% stock/used parts in it anymore. If it wasn't for who the gun's going to, I wouldn't even have bothered.

hmm just thought id confirm this.. Only other problem to your power loss could be the cut off lever not liking the new mechbox, might need some filing.

IF your having gear jam issues, shim problem or bushings not seating in the mechbox propperly, thats if you used the same ones from the JG... Id have to see it first hand to really be able to diagnose, could be mismatching parts, or many other small un-thought of issues. As you said its cursed, I had an ICS like that, ran through every problem in the book one after the other till i got it to cooperate, then I sold it :)

Good luck man.

Thanks man. Appreciate it.

cutoff was swapped to see if that was the problem. didn't help or make it worse. both swing smoothly. one of the first things I did was to make sure it wasn't over tightened.

may have possibly figured out the problem by accident.

tonight I decided to install a non ported cylinder I picked up Monday as I've been using a 509mm TB in my M4. I also went ahead a rewired it as the old wire was frayed and I changed from a full stock to a collapsible and wanted to eliminate the connector.

when closing it up I noticed I bent the trigger spring by pushing it down to hard. figured it wouldn't cause a problem. threw a screw into hold it all in place and tested the trigger and I ended up with the same clicking on semi. since, that spring was the only anomaly I swapped it out, sadly with an mp5 spring which is significantly stiffer. slapped it all back together and what do you know? fires perfectly. So when I muster up the will to deal with the budget build, I'll post back.

Cliff notes: Don't bend down your trigger spring when you install it!

Well, there's still something wrong with the switch assembly. Thought I had it when I assembled everything and the trigger was smooth as silk. Too lazy to break the box down again. The trigger spring does need to be straight though. It does solve one of the problems lol.