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Discussion Starter · #1 ·
I recently came by 2 aeg’s which were really old. One was an Ak-47, which when you pulled the trigger just made a small click. The other worked fine. I wanted to fix the ak-47 because it looked cool so I opened it up and watched a couple you tube videos and realized that because I had no idea what I was doing I had stripped the piston. So I took the working gearbox out of its gun and put it in the ak-47 (they are both v3 gearboxes), for a while it worked fine and then recently it just started to do the same clicking thing that the other gearbox had done. This usually happened when it was low on battery, but I charged the battery up fully and it still did it. I lowered the motor height and it made a grinding noise that didn’t sound good so I raised the motor but then it started clicking again. I ordered a new battery and am waiting for it but I was just wondering if anyone knew what was wrong. I really don’t want to disengage the ARL or open up the gearbox because I don’t really know what I’m doing.
 

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What battery were you using before? NiMH, LiPo? Was this in semi or auto? If semi, did you try shooting it in auto? Can you tell if the click is coming from the trigger area or the motor?

A clicking noise can indicate the battery or motor are not strong enough to cycle the gun from its present state, a trigger switch that's awkwardly parked (semi lockup), reversed polarity, fuse/wiring issues, etc
 

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Is there a sweet spot between the grinding and the clicking? How far do you have to raise the motor from where it's grinding before it starts clicking?

Does it sound like the same sort of grinding as the first gearbox? Can you describe the sound or maybe post a video of it firing? Did you open the first gearbox and visually see a stripped piston, or is that just an educated guess (often a stripped piston will sound like a grinding "whirrr", not a click)?

To me that sounds like a locked up gearbox or bad motor, but I don't want to recommend a new motor until I have more details. Sorry for the torrent of questions, I'm trying to get as detailed a picture as possible. Any idea of the brands?
 

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TBH I don't know how to either. I've never uploaded one. There's probably a minimum post requirement though.

Totally sounds like a locked up gearbox.
 

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forgot to mention but when it locks up the battery starts to smoke
Generally a good time to stop pulling the trigger lol

Sounds like your motor is unable to cycle the gearbox and is effectively shorting the battery. Could be the battery can't supply enough power to complete the cycle when the piston gets parked rearward due to overspin, could be the motor is worn out or doesn't have the torque needed, could be jammed up due to a internal failure of some sort. Pictures may help.

You might be better off getting a local tech to sort it out for you, or acknowledge that you can't break it if it's already broken and dive in, learn how to open it up and fix the issue. Probably needs a service and new motor.
 

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Discussion Starter · #10 ·
Generally a good time to stop pulling the trigger lol

Sounds like your motor is unable to cycle the gearbox and is effectively shorting the battery. Could be the battery can't supply enough power to complete the cycle when the piston gets parked rearward due to overspin, could be the motor is worn out or doesn't have the torque needed, could be jammed up due to a internal failure of some sort. Pictures may help.

You might be better off getting a local tech to sort it out for you, or acknowledge that you can't break it if it's already broken and dive in, learn how to open it up and fix the issue. Probably needs a service and new motor.
I think I’ll go at it myself because I don’t want to have to pay for someone to fix it when I might be able to do it myself and also the nearest airsoft shop is hours away
 

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Discussion Starter · #11 ·
Ok a couple things I forgot to say.
The gear on the end of the motor somehow lost the Allen screw that holds it to the motor. I dont think this affected anything but I’ll put in a pic of it. also the old gearbox was locking up also so I lowered the motor and now it works well ( except for the fact that the piston is stripped)
The missing screw:
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After listening to your video I've changed my diagnosis. Sounds like it's grinding on something. Is that the clicking you were talking about?

Looking at the gearbox tells me it is a Crossman brand AK-47U, complete with a plastic shell and gears. The pinion gear (on the motor) is steel, and that creates the unwanted result of a structural metal on plastic mesh.

I've actually seen this before with exactly the same symptoms and gun. The bevel gear is likely stripped where it makes contact with the pinion.

I was able to replace the gears with a full metal set but it also required a tappet delay chip to feed properly. Just a heads up though, this is a difficult project on a fairly low quality product. It may never cycle properly again.

Was the other gearbox the same?
 

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Maybe swap the working piston from the current box and put it in the original one.

Edit: You actually recommended this a few posts ago, I'm just behind everyone lol
 

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Discussion Starter · #14 ·
After listening to your video I've changed my diagnosis. Sounds like it's grinding on something. Is that the clicking you were talking about?

Looking at the gearbox tells me it is a Crossman brand AK-47U, complete with a plastic shell and gears. The pinion gear (on the motor) is steel, and that creates the unwanted result of a structural metal on plastic mesh.

I've actually seen this before with exactly the same symptoms and gun. The bevel gear is likely stripped where it makes contact with the pinion.

I was able to replace the gears with a full metal set but it also required a tappet delay chip to feed properly. Just a heads up though, this is a difficult project on a fairly low quality product. It may never cycle properly again.

Was the other gearbox the same?
The other gearbox is metal
I think I’m just going to take the piston out of the plastic gearbox and put it in the metal one
 

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Pop the AR latch before opening the gearbox, will save you some pain. V3 shells are nicer to work on than v2, spring guide usually does a good job staying on place etc. Best of luck! Keep us posted :)
 

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That screeching is not "Clicking".

As other have mentioned above, mechbox is locked or jammed.
 

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Discussion Starter · #17 ·
UPDATE:
Ok, good news and bad news. I swapped the pistons and the metal gearbox worked, the reassembly took a while but I eventually got everything back together. The only thing is now it doesn’t fire in auto and I can see that the trigger assembly isn’t pushing the metal connector thingies together. But it’s weird because it works in semi. Anyone know what’s up?
 

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Did you assemble the fire selector correctly? Is the trigger stopping before it should or does it feel like it's going as far as it does in semi?
 

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Discussion Starter · #19 ·
Did you assemble the fire selector correctly? Is the trigger stopping before it should or does it feel like it's going as far as it does in semi?
I 99% sure that I assembled the selector switch right. And the trigger feels the same in semi and auto but in auto it feels like there’s less resistance. Like it’s not making contact with the connector thing
 

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Did you possibly forget the cutoff lever spring (I forget whether not having it disables full auto or semi auto)?
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This is actually a V2 gearbox but it is good enough for illustration purposes.

Edit: I'm pretty sure it disables semi auto if you don't have it, sorry for the confusion. It's been a while since I forgot it. :rolleyes:
 
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