Another servo issue.

[GeneralTyphon]

Outcast 6s EXB had no issues besides the stock servo was barely moving under the weight of the truck. Decided to go with HobbyStar HBW-4724HV

With everything powered off I plugged the HobbyStar (with brown wire as negative) into the receiver.

After turning the transmitter and car on. I noticed there was 0% battery level indicator on the remote, no throttle, the servo didn't move and the red light on the ESC was fast flashing red indicating LVC. Installed a known working servo and it worked fine. Rebound the controller to the receiver OK, attempted to re-calibrate the ESC, failed and always fast flashing red.

Ended up trying a known good receiver and servo, the truck operated normally.

Admitting defeat, bought a new Spektrum SR6110AT, and exchanged the junk servo.

After replacing the servo (again) and receiver, transmitter bound and calibrated perfectly the first time.

Seems like the first HobbyStar HBW-4724HV somehow took out the IC that monitors battery voltage in the SR6110AT preventing the ESC from arming during start up.

Is anyone able to confirm what happened here?

 

[Jerold]

Seems like the first HobbyStar HBW-4724HV somehow took out the IC that monitors battery voltage in the SR6110AT preventing the ESC from arming during start up.

You mean the HobbyStar servo killed the receiver?

Not likely, but it's made in China so who really knows, they don't know 1/2 the time. Anything is possible or it could be a coincidence of failures as in the receiver and servo failed at the same time.

The battery voltage monitor port to the receiver comes from a different connector, and is not connected to the servo power or signal leads at all. The GND should be common through out your car. It's possible the +/- on the voltage connector were swapped and shorted them. But I think your battery and/or your ESC would have been unhappy as well. Note the connector is keyed, but not marked and with the small connectors it's pretty easy to jam them in there backwards. So that's possible.

The voltage port on the receiver is just information that is sent to your radio. If unplugged, it's 0V, but it the receiver shouldn't care nor be implementing LVC, that's 100% and ESC function.

In any system you one one guy in charge and the rest take the orders. If you allow the receiver to make a decision the ESC normally makes you don't really know who's in charge and that's a problem. It's how robots go rogue, which can be a bad thing.

I could be missing something but I'm not sure how the servo could kill the receiver. The servo doesn't provide any power to the receiver, there is no source for it.

It possible there could be a short between the power and gnd on the bad servo. Even in this worst case scenario it "shouldn't" ruin the receiver. The pins on the receiver are bused together and the voltage would drop to 0V at the receiver. The power source (ESC) would be over current and probably (hopefully) kick in a breaker.

It's a very crude diagram but hopefully it explains the connections.

1. I would see if the servo leads are shorted (+/-).
2. Also check the polarity of your battery monitor plug and make sure it's plugging in correctly.
3. If you have a servo tester use it to check out the servo

 

[GeneralTyphon]

I already swapped it out for an exchange, or I could further test it. Everything works fine now. Just wondering if this was possible. Sounds like it would have to be extraordinary circumstances to kill the magic in the receiver. Thank you for the detailed reply

 

[Jerold]

I already swapped it out for an exchange, or I could further test it. Everything works fine now. Just wondering if this was possible. Sounds like it would have to be extraordinary circumstances to kill the magic in the receiver. Thank you for the detailed reply

Yes, I think it's unlikely that the servo can damage the receiver based on what I can see. But others may have seen something similar, you never know.

Best of luck.

 

[RC Steve]

It's pretty hard to kill a receiver. I've plugged every wire that goes to the receiver in backwards and/or in the wrong slots including servos that would brown out everything. Never kill a receiver.

 

[morrjr71]

I have had a bad servo take out a channel in a receiver. It can happen.

 

[SrC]

I already swapped it out for an exchange, or I could further test it. Everything works fine now. Just wondering if this was possible. Sounds like it would have to be extraordinary circumstances to kill the magic in the receiver. Thank you for the detailed reply

I am surprised that the BEC circuit of the ESC did not also fry. Which is usually the case. Maybe you just caught it in time.
Good luck.
I run DS3235 35kg AMZ $34.00 servos in all of my RC's. 6s models and all my Crawlers. Like 9 of them so far. Many at 7.4v BEC settings.
No issues.

 

[Lil Dylan]

I'm curious. Is there anyway to run the battery voltage feature for my dx3 when running my castle escs? I'm not sure what I'd need to make that work. I'm using non-smart batteries. Thanks.

 

[jkflow]

I'm curious. Is there anyway to run the battery voltage feature for my dx3 when running my castle escs? I'm not sure what I'd need to make that work. I'm using non-smart batteries. Thanks.

Simple answer - No

 

[Lil Dylan]

Simple answer - No

Is that because of the esc or "dumb" batteries?

 

[jkflow]

It's a function of the ESC not talking to the receiver in the right format (or any for that matter). Lipos have nothing to do with it.

 

[Lil Dylan]

It's a function of the ESC not talking to the receiver in the right format (or any for that matter). Lipos have nothing to do with it.

Gotcha, thanks.

 

[SrC]

Is that because of the esc or "dumb" batteries?

The Dumb Batteries have no BattGo Chip inside. Yeah, and Dumb lipos are actually the Smarter way to go.
Spektrum Marketting only tells you otherwise. Those 3 DX3 voltage power lights are not accurate anyway. A Very Rough estimate. You don't need it. It is just fluff.
The ESC will go LVC when the pack is done. All you need to really know.
If you want a real lipo voltage display, toss that DX3 and get a $80. Radio Link Radio, RC6GS and use the Telemetry Receiver with it. Works for me.

 

[jkflow]

If you go Radiolink, just be aware that you have to solder wires to your battery/ESC leads and feed them into teh receiver.
Works like a charm and Radiolink is my go-to for anything non Firma.