Steering servo seems to have died in a way I've never seen, need some thoughts on it.

[ApostateTapir]

Here's my set up:

• SCX10 II
  
• Holmes Hobbies motor
  
• Hobbywing 1080 ESC
  
• 3s 1300mah LiPo
  
• Spektrum DX5C TX
  
• Spektrum SR6100AT RX
  
• EcoPower WP120T servo

My 1080 is set to put out 7.4 volts and, based on my receiver telemetry, it puts out a very consistent 7.3-7.4 volts. My servo is ran straight into the receiver, so it relies on the 3 amp max internal BEC of the 1080. I have steering in STR, throttle in channel THR, and a pair of 5mm LED lights in AUX 1, which I've programmed to turn on and off with a button on my TX.

Last night, I was replacing a servo horn, not due to a crash or anything, just swapped to a different truck. I was setting my trim/end points and was moving the steering back and forth quite a bit to get it all dialed in. This was on my desk with nothing in the way of the tires, when suddenly my steering went super sluggish and made the sound of an electronic running out of battery power.

At first I thought maybe it was my LVC on the 1080, because it is set to high. But I didn't hear a beep or anything and it didn't cut off immediately. I measured my LiPo and it was 3.7v per cell. Regardless, I charged the battery up and moved the ESC LVC to low, but still had the same issue. While I was moving it back and forth, the servo just stopped moving entirely, and now makes no noise and doesn't do anything under steering input.

I started trying to diagnose what happened and ran across some very weird things.

1. When I have the dead servo hooked up, my Aux 1 channel doesn't function. The radio shows it working, but the lights do not turn on or off.
   
2. I set the ESC voltage to 6 volts and when I plug the stock Tactic TSX45 servo in, it functions perfect along with my Aux 1 lights. The dead servo doesn't work at 6v either.
   
3. The throttle channel is completely unaffected by either set up.

So I'm trying to figure out why I blew a $70 servo in less than two weeks of running and it died while sitting on my bench under no load from obstacles. I have not ran this servo hard, it has maybe 3 hours of drive time on trail/light crawling type terrain. I haven't been abusing this thing.

I'm going to the hobby shop today to get a refund on the servo and choose another one. At this point, I'm ready to just drop the $150 on a top end servo and $25 on the Castle 10a BEC. But I'm wondering if you more experienced folks have any idea what happened here and how to avoid it going forward.

The ESC has an internal 3 amp BEC. Does this mean that when the servo pulls 3 amps, the ESC just doesn't let it draw any more? Or does the servo pull more amps than the ESC is rated for and that could cause a problem? The hobby shop told me that I could run a high voltage servo off the 1080 alone without BEC, no problem. If that's not the case, I'm gonna be kinda annoyed.

Thank you all for reading this wall of text and a preemptive thank you for any thoughts or help.

TL;DR - Servo went sluggish while on the bench and died shortly after. Aux 1 lights don't work with dead servo plugged in. Plugging in stock servo makes everything work as normal again.

[bryantjt]

Sounds like it just plain died. I just started using NSDRC servos, https://nsdrcscaleparts.com/shop/ols/products/rs800, these don't use a bec, you plug them directly into your main battery. It seemed odd at first but my buddy swears by them and for the power output they are very reasonably priced.

[mtnyote]

FWIW I just ordered 2 of these servos to test out in my Capra kit. Price is reasonable and the torque is insanely high. Also, no need for a bec as it’s directly wired to the battery. ( https://holmeshobbies.com/electronic...800-servo.html )

[ApostateTapir]

Thanks for the responses guys. Hobby shop figured it was backfeeding, returned it under warranty and upgraded!

[ferp420]

thats great the shop warrented it in my opinion as soon as you added the lights you were drawing to much power for the bec to handle that servo just brownd out
if you dident get a direct power servo get a external bec

[ApostateTapir]

Originally Posted by ferp420

thats great the shop warrented it in my opinion as soon as you added the lights you were drawing to much power for the bec to handle that servo just brownd out
if you dident get a direct power servo get a external bec

I wondered the same thing, but unplugging the lights didn't fix it and it ran fin with the stock Tactic servo. I do have a Castle 10A BEC on its way to run the new servo.