RC Tank Warfare community hobby forum

This is a weird one. I have a Clark TK22 that I installed in the Project 704 build. Installed a servo recoil which works fine, and added a traverse which I connected another servo up to.

The servo is plugged into the receiver not the board, but when operated under load (the traverse is friction free, light finger pressure will swing the barrel back and forth) the light on the receiver starts flashing, and the tank adopts a mind of it's own? Turning the knob on the tx randomly starts the tank, shuts the board down, fires the gun, and causes it to start jerking. I have exactly the same set up on another SPG and it works perfectly? The barrel hardly moves at all just glitches like mad unless the traverse is centered.

The servo isn't even connected to the TK22 board??

My next option is to use the servo elevation option on the board and see if it will function from there. Grrr!!

Have you tried it with a separate receiver battery? Could be browning out?

Just been reading on the intraweb, seems that the aircraft guys have the same problem. Cheap copies flooding the market, that have no torque and jitter like mad. One guy posted a pic of a burnt out control board that crashed his plane. They are supposed to be Towerpro MG90S, steel geared. Even finger pressure on the arm will cause problems.

I can adjust the barrel to a fixed straight ahead position for now, but I have four of these and none of them are any different, I even swapped the rx out, it was just the same.

There was a time when only expensive products (like Rolex watches) were faked, not any more. It is getting harder & harder to buy genuine quality goods especially when ordered online. Sadly for a lot of purchases online is the only place to buy, where I live (NE England) most of the model shops have long gone.

Where & when did you buy the servos?

Got them off Ebay, description said they were in the UK, but they took about 2-3 weeks to get here. Safe guess as to where they came from?

rochesb wrote:There was a time when only expensive products (like Rolex watches) were faked, not any more. It is getting harder & harder to buy genuine quality goods especially when ordered online. Sadly for a lot of purchases online is the only place to buy, where I live (NE England) most of the model shops have long gone.

Where & when did you buy the servos?

From the Rolex to the humble servo, it seems that China makes the majority of 'genuine items' these days, as well as most of the counterfeit clones. The real feat, however, has been in counterfeit Porsches, lately. Yep..that's a 'Porsche' car with a Ford engine lurking in the boot, and with sounds to replicate the roar of the real thing ( counterfeit Benedini perhaps? ).
https://www.wired.com/2011/01/st_counterfeitcars/

I should have read the feedback...lots of negative comments about fake goods etc.

I have now asked for a refund and will see what happens. Ironically I used an old plastic geared servo on the recoil, which has more friction to overcome and it works perfectly?

A very strange problem indeed. It's almost as if there's a gateway fault in the RX caused by the presence of the dodgy servo. The 'gateway' then allows all possible instructions to reach the board from the TX to the RX, the instant that a signal is sent to activate servo movement. I had a PCB fault on my old Volvo 480 ES that produced weird results like that. Dipping the headlights switched on the rear wiper, and engine management ECU went into 'climbing a hill in Winter' mode just because the outside temp thermometer meter read '-2deg', though it was actually summer's day. Ironically, this was long before China bought Volvo off Ford.
All of the problems came from green corrosion on the main ECU pub traces...occasioned by condensation and damp. Thinking along those lines, ..I'd guess that the wee pcb in the servo has dodgy traces and is shorting out. It may even have damaged the RX. Hopefully not. Just a few observations.

Could the servo be generating electrical RF 'noise' interference & upsetting the RX?

Whatever the reason, not good. It only goes to show how easily we can be caught out by dodgy suppliers. I am wary of buying from eBay especially outside the EU. I sometimes use Google Maps to track down the address of UK suppliers unknown to me or without good references to see if they look genuine. Also, if I cannot find a registered address for a trader online I look elsewhere.

I buy 2nd hand servos on eBay, a tank can't fallout of the sky . Think most are out of crashed planes.
Dirt cheap , build my own servo recoil units with the standard size ones also good for turret motor /elevation.
Only problem with the larger servos is space and hitting slipring at max elevation.
Bust my recoil a few times bumping into things, if you can build it you can fix on the cheap.