Hi all,

I've got this weird problem with my T-34 (it's a 6.0).  The main cannon isn't firing correctly - instead of trying to load the airsoft gun (the feed for which is closed off) and firing (which involves the tank making the loading sound followed by the tank firing and recoiling), it's just loading and shuddering, and loading and shuddering, without ever firing.

I'm planning to upgrade the board to a 7.0 anyway, but is there anything I can do to fix this in the meantime?

Sounds like the recoil trigger is stuck closed and is continually looping the recoil sound/track effect.

Jarlath wrote:

Sounds like the recoil trigger is stuck closed and is continually looping the recoil sound/track effect.

Okay...

How do I fix that?

It is located in the turret.
You will need to take the tank apart though.

Remove upper from lower hull. Check to see if any wires have been chewed or pinched by the turret ring.

Remove the turret from the upper hull. (aka remove the turret ring).
Then remove the lower turret floor. Be careful to not lose any screws/springs...

On the airsoft/recoil unit, The trigger switch usually is secured into the airsoft unit by a single screw. 

Usually there is a small sliver of black plastic separating the trigger fingers.



All this does is control the Cannon sound effect and the initiation of the track recoil when the circuit is completed (aka the end of the metal arms touch. I believe you can fully use the tank with airsoft even if you disconnect this switch from the MFU, you just lose sound and track effects.

CN6 is the offending connection on the MFU

Jarlath wrote:

It is located in the turret.
You will need to take the tank apart though.

Remove upper from lower hull. Check to see if any wires have been chewed or pinched by the turret ring.

Remove the turret from the upper hull. (aka remove the turret ring).
Then remove the lower turret floor. Be careful to not lose any screws/springs...

On the airsoft/recoil unit, The trigger switch usually is secured into the airsoft unit by a single screw. 

Usually there is a small sliver of black plastic separating the trigger fingers.



All this does is control the Cannon sound effect and the initiation of the track recoil when the circuit is completed (aka the end of the metal arms touch. I believe you can fully use the tank with airsoft even if you disconnect this switch from the MFU, you just lose sound and track effects.

Okay, so I've it apart.

No pinching of wires.  That said, the spacer does not look like it does in your picture.  My wife just took a picture of it, and it is attached.

What appears to be happening at the moment is that the the airsoft gun just keeps loading and firing, and the tank track recoil and firing sound are not being activated (the shuddering I referred to was not track recoil, but the barrel shuddering as the gun fired).  It does go through the full loading and firing, however - it is literally [loading sound]-CLICK-[loading sound]-CLICK, and it does not stop loading and firing while the buttons on the remote are pressed.  When I tested the tank while it was open to see if rotating the turret would help fix it, I got visual confirmation of movement at the trigger side when the click happened.

EDIT: Fun fact: the wiring diagram provided by Heng Long bears no resemblance WHATSOEVER to the actual colours of the wiring in the tank.  I had to open up my Tiger so that I had a reference for putting the T-34 back together.  Sheesh.

OK. you made it sound as though you were getting track recoil... But you have continuous Airsoft motor running.

I assume you are not pressing to two shoulder buttons to make the tank fire?

The two yellow wires from the trigger switch should go to a connector that is plugged into CN6
From the small motor in the white BB unit shown, trace the two wires, the motor wires SHOULD go to CN10 on the HL6.0 MFU.

Jarlath wrote:

OK. you made it sound as though you were getting track recoil... But you have continuous Airsoft motor running.

I assume you are not pressing to two shoulder buttons to make the tank fire?

The two yellow wires from the trigger switch should go to a connector that is plugged into CN6
From the small motor in the white BB unit shown, trace the two wires, the motor wires SHOULD go to CN10 on the HL6.0 MFU.

Pressing the two shoulder buttons is how the tank fires, so they are being pressed.  I pretty sure those are the locations that the wires are going into.

Is this a control board issue?  I mean, I am planning to upgrade to a 7.0 anyway, it's just a question of when I can put the money together for it.

OK. I must have read the first post wrong then...

This T-34 has a combination BB/recoil system?

Is the issue that the tank, once you activate the BB cannon, cycles the BB motor and experiences Track Recoil, but does not give the firing sound and does not have barrel recoil?

Jarlath wrote:

OK. I must have read the first post wrong then...

This T-34 has a combination BB/recoil system?

Is the issue that the tank, once you activate the BB cannon, cycles the BB motor and experiences Track Recoil, but does not give the firing sound and does not have barrel recoil?

Okay...so, to clarify:

The tank is a Heng Long 6.0.  It has a combination BB/IR system with track recoil (and no barrel recoil).  What should happen when the tank fires is the BB motor cycles, the BB gun fires (causing the barrel to shudder), and the firing sound is played and track recoils.  Once this happens, the BB motor shuts down and the BB gun cannot be fired again unless the two shoulder buttons are let go of and pressed again.

When the tank fires right now, the BB motor cycles and the gun fires, and then the BB motor immediately starts cycling again, and the gun fires, and the BB motor immediately starts cycling again, etc.  There is no firing sound or track recoil.

OK. No sound or track recoil on firing is definitely a failure in the trigger switch circuit. I am also pretty sure the switch acts as a signal stop to the BB motor relay.


When the BB unit spins up, it retracts the BB piston until it trips the release, Near this point it also should close the trigger switch which closes the circuit to signal sound & track recoil.

Jarlath wrote:

OK. No sound or track recoil on firing is definitely a failure in the trigger switch circuit. I am also pretty sure the switch acts as a signal stop to the BB motor relay.


When the BB unit spins up, it retracts the BB piston until it trips the release, Near this point it also should close the trigger switch which closes the circuit to signal sound & track recoil.

Okay...so, what is the fix there, then?

I assume the continuous shot is what you are experiencing... (starting at @2:38 in video)
Not my video..



If you can remove the switch and during a BB shooting effect, attempt to bridge/short the circuit. 

If it stops the BB Cycling and causes recoil & sound, then it may be an adjustment on the mount which will be possibly the following.

• mounting the larger black bumper of the trigger switch closer to the front of the bb unit so it makes contact easier.
  
• Narrowing the gap between the contact sides of the trigger switch (aka bending the back most blade so it is closer to the front blade with the bumper.)
  

If it does not stop the cycling, turn the tank off and then back on and try again, but remove the connector from CN6 on the MFU. Initiate the BB cycling and using a pair of tweezers short the two pins in CN6.

• If it stops/recoils/sound effect, it will be a wiring/trigger switch issue, and replace it.
  
• If it does not stop , it is a fault in the MFU.
  

Jarlath wrote:

I assume the continuous shot is what you are experiencing... (starting at @2:38 in video)
Not my video..



If you can remove the switch and during a BB shooting effect, attempt to bridge/short the circuit. 

If it stops the BB Cycling and causes recoil & sound, then it may be an adjustment on the mount which will be possibly the following.

• mounting the larger black bumper of the trigger switch closer to the front of the bb unit so it makes contact easier.
  
• Narrowing the gap between the contact sides of the trigger switch (aka bending the back most blade so it is closer to the front blade with the bumper.)
  

If it does not stop the cycling, turn the tank off and then back on and try again, but remove the connector from CN6 on the MFU. Initiate the BB cycling and using a pair of tweezers short the two pins in CN6.

• If it stops/recoils/sound effect, it will be a wiring/trigger switch issue, and replace it.
  
• If it does not stop , it is a fault in the MFU.
  

Probably easier to test the MFU first (among other things, I don't need to take everything apart to get at the gun again)...now I just need to get my hands on some rubber gloves...that could take a couple of days...

But, testing coming soon, and many thanks for the help in sorting this out!