Receiver doesn't work properly when servos are plugged in

[SkyEye]

I'm trying to salvage the electronics from my old Parkzone T-28 Trojan, so I took all the electronics out and hooked it all up. The transmitter binded to the receiver and the ESC and motor just fine. I got full control of the motor. However when I went to connect the servos into the receiver, the receiver LED started flashing very dimly. And when all servos are plugged in the receiver won't work at all. I thought it was a bad servo but the same happens with all of the servos. Is it possible they are all bad? Please let me know. I have a Dx6i, with a spectrum AR600, 30A ESC

 

[PsyBorg]

Were they all working the last time you used them or did the aircraft they came out of it meet its end in a crash? How are you powering it all? Did you grab a battery pack that is not charged? We have ALL done that one and scratched our heads for a while thinking we had a problem.

 

[LitterBug]

It's possible that the BEC on the ESC is damaged and cannot provide enough current to run the servos. Have you tried each servo individually, and on different RX ports?

LB

 

[Tench745]

As alluded to above, you may have a servo or two that is binding/bad and over-drawing the BEC. Or the BEC may be faulty. Testing things systematically will help answer your questions.

 

[SkyEye]

I'm using a 3 cell 1800mah. I haven't used the electronics since the plane crashed (nose dive from about 100ft up). Yes I think the ESC has gone bad. How is it though that the ESC can handle the power of the motor but not a little servo?

 

[LitterBug]

The BEC is a separate circuit.

 

[Merv]

How is it though that the ESC can handle the power of the motor but not a little servo?

The servos draw power from a separate circuit inside the ESC, called a BEC, battery elimination circuit. It drops the voltage from the battery down to 5v, something the Rx & servos can use.

 

[SkyEye]

Oh okay gotcha. Sorry, I'm getting back into RC after a 4-5 year break and so I'm re familiarizing myself with all the electronic components and terminology. Should I get a new ESC then? or is it possible to just replace the BEC? (I am horrible at soldering)

 

[Merv]

Oh okay gotcha. Sorry, I'm getting back into RC after a 4-5 year break and so I'm re familiarizing myself with all the electronic components and terminology. Should I get a new ESC then? or is it possible to just replace the BEC? (I am horrible at soldering)

I’ve never seen anyone repair an ESC, I’m sure it’s possible. I’d get a new one.
When looking for a replacement, look for an ESC with a BEC with a minimum of 3 amps, preferably 4-5 amps.

 

[PsyBorg]

two options are either replace the esc and be aware of current requirements and get one with an adequate bec or keep that esc and get a separate bec that meets the current requirements.

 

[SkyEye]

Will it hurt my electronics if I switch up to a 35A ESC? The broken one is a 30A ESC

 

[Bricks]

Will it hurt my electronics if I switch up to a 35A ESC? The broken one is a 30A ESC

Nope.

 

[Ketchup]

Have you tried rebinding? I have had situations where a receiver was bound, but if I added or removed a servo it didn't work. I had to rebind before it worked again. Rebinding might not work, but it might be worth a shot.

 

[Merv]

Will it hurt my electronics if I switch up to a 35A ESC? The broken one is a 30A ESC

The amp ratings on everything RC are do not exceed ratings.

It all starts with the prop, larger props pull more amps than smaller ones. Spinning a prop faster pulls more amps. If a motor has a 30 amp rating, use a 35 amp ESC, a few more amps to handle the Rx & servos. Make sure the battery can supply the total amps. If you overload your system, the weakest link, motor, ESC or battery, will give out first. It’s perfect fine to a component with a larger amp rating, you just don’t want to exceed any rating.

For batteries the amps are calculated, the formula is MAH / 1000 x C = Amps
Example a 2,200 mah 20C can supply 44 amps (2200/1000*20=44)
Sometimes a battery will have 2 C ratings, a continuous & burst. Use the lower continuous ratings, the bust ratings is for a burst load of 10-15 seconds.

 

[LitterBug]

Sometimes a battery will have 2 C ratings, a continuous & burst. Use the lower continuous ratings, the bust ratings is for a burst load of 10-15 seconds.

I've often wanted to pull the burst rating (or higher) till one bursts....