v3 gearbox semi occasionally gets stuck as if its in safe

[egone140]

Hi All,
I got a new budget AK for christmas and immediately set about upgrading some bits, chief among these upgrades was an active braking mosfet and a new high torque motor.

The Problem:
When fired on semi I'm experiencing an intermitent fault where the trigger is acting like its on safe i.e. it will not let me pull the trigger again, NOT that the trigger gets stuck and won't go back to its resting / ready to pull position as is the more common problem. At the minute i'm just switching it to full auto and back which temporarily fixes the problem on semi.

I think we can rule out the external selector plate because its not being moved but as I'm not too familar with version 3 boxes I was wondering if anyone new why this is happening and how to fix it.


Thanks.

[caffin999]

Re: v3 gearbox semi occasionally gets stuck as if its in safe

Hi All,
I got a new budget AK for christmas and immediately set about upgrading some bits, chief among these upgrades was an active braking mosfet and a new high torque motor.

The Problem:
When fired on semi I'm experiencing an intermitent fault where the trigger is acting like its on safe i.e. it will not let me pull the trigger again, NOT that the trigger gets stuck and won't go back to its resting / ready to pull position as is the more common problem. At the minute i'm just switching it to full auto and back which temporarily fixes the problem on semi.

I think we can rule out the external selector plate because its not being moved but as I'm not too familar with version 3 boxes I was wondering if anyone new why this is happening and how to fix it.


Thanks.

sounds like standard semi lock up if full auto is clearing it every time. you need to be careful with trigger discipline. pulling it fully on semi will solve the problem.

although you would think that wouldn't really be a problem with a high torque motor and ab mosfet. are they currently installed? are you sure the mosfet is ab? did you experience the problem before the install?

I have never had semi lock up with a high torque motor and ab mosfet....

[egone140]

Re: v3 gearbox semi occasionally gets stuck as if its in safe

Hi thanks for the response.
Yes these parts are currently installed and as this was a brand new gun I couldn't tell you if this problem was already there or not. The mosfet is AB but that alone doesn't guarantee the motor would stop instantly all an AB mosfet does is create a short across the motor stopping it alot quicker but the time it takes to stop can vary based on motor etc

I only use the semi in CQB and my trigger discipline is usually pretty good though at certain times in CQB it can be frantic to pull the trigger enough. I will definitely look into this and try it out the first chance I get.

I read up that this can also be caused by low voltage systems but I'm running deans and a 9.6v battery. My current thinking is that the motor is either stopping early or running on a bit and causing the cut off lever to either remain engaged or set it to be engaged.
I can tell you that the main spring is uncompressed and the piston if fully forward after every shot on semi so I have no idea why the cut off lever could still be engaged. Any idea's anyone? I think my next step will be to disassemble and take a good hard look at how its all sitting together perhaps the cut off lever is loose or something. Failing that I might try putting some high speed gears in when I get the funds together to buy some.

[egone140]

Re: v3 gearbox semi occasionally gets stuck as if its in safe

Thought I'd update this:
After disassembly I discovered the lock up is being caused by the motor stopping too soon leaving the cut off lever engaged. I decided to install high speed gears which have dramatically reduced the problem however to truly resolve the issue all I would have to do is install a non active breaking mosfet but at the minute its not really causing me any problems so I won't be replacing it any time soon.