Savox Servo causing ESC to cut out

[mikeyscott]

Hi,

I've just fitted a Savox servo into my B4 and when I turn full lock to the right it cuts drive to the motor. I have reduced the amount of avaliable steering in my KO EX-5 Radio and the problem seems to have stopped. Any reason why?

It's plugged into a LRP Super Sport Digital ESC.

[super__dan]

Crap BEC on the speedo causing it to cut out under load (of full steering lock).

[mikeyscott]

Oh bugger, so what do I change to? Looking at an LRP 7.1 on ebay, would that fix it?

I have a 1001 KO FET in my spares box, so that as well?

Got a Tekin 700 Pro Plus in the box too

[super__dan]

I've assumed that, but it stands to reason, a lot of the budget ones have low voltage and low current BEC's to save space/money.

If that is the issue then your options are, different speedo, different servo (a 7.2V servo would irradicate this problem and is one of the reasons I run a KO 2123 in all my cars) or a 'power cap' for the receiver. Something like this, http://www.shopatron.com/product/pro...=NOV5626/135.0 which will keep the voltage high enough in the recevier to stop it cutting out.

[captain-codpiece]

I had the same problem, as I was still running old skool 27 mhz. Then I tried a Novak XXL receiver and it sorted it straight away. So it does seem like cheap receivers can't handle it.

[mikeyscott]

Mm, I am also running my 40Mhz AM KO Propo Reciever from back in the day. It too is circa 15 years old. What 40Mhz AM recievers would people recommend?

Also sounds like my Ko 1001 FET might be going back in the car after all...

[mikeyscott]

Originally Posted by super__dan

I've assumed that, but it stands to reason, a lot of the budget ones have low voltage and low current BEC's to save space/money.

If that is the issue then your options are, different speedo, different servo (a 7.2V servo would irradicate this problem and is one of the reasons I run a KO 2123 in all my cars) or a 'power cap' for the receiver. Something like this, http://www.shopatron.com/product/pro...=NOV5626/135.0 which will keep the voltage high enough in the recevier to stop it cutting out.

That won't work as I've only got two inputs on my receiver

[mikeyscott]

So what is the best thing to change -

1) The speedo?
2) The receiver?
3) The servo?

I'll prob give DMS a call on Tuesday, but I didn't particularly want to part with my 40Mhz AM Ko EX-5 radio

[super__dan]

Well if you have a 1001 (they were 7.2V right?) try that, if it goes away then you've narrowed down your options. You can get Y leads that you could then add the cap into.

I must admit I hadn't considered the receiver, could be, being that age it's more sensitive than modern receviers for voltage, though again the cap might fix that.

Other options, can you borrow other speedo to try, something with a bigger BEC output. If you're running brushed I remember Novak (GT7) and Tekin (G10 / G11) both had big outputs, 6.0V 5A IIRC.

[mikeyscott]

I'll have to get some wire for my 1001 Fet and yes they are 7.2v and go from there. I used to run the servo with my current radio gear and a Tekin 700 Pro Plus with no issues.

Yes I'm running brushed at the moment as I'm only just coming back to RC Racing after a very long break, so will see how I get on before splashing more cash etc.

Interesting that you mentioned about these y spliters, I'll look into ordering one of these anyway with some KO Fet connectors etc.

[terry.sc]

Originally Posted by mikeyscott

So what is the best thing to change -

1) The speedo?
2) The receiver?
3) The servo?

Get a separate BEC. The cheap option is the 5A UBEC systems, they are all over ebay. The decent one is the Castle Creations BEC with up to 10A output and programmable with the Castlelink interface to adjust the voltage in 0.1v steps.

I run crawlers and the servos used in them have pretty extreme power requirements, no built in BEC has the power to drive them. Adding a separate BEC gives the servo all the power it needs.

[mikeyscott]

ok I'll look into this although I would rather have less in the car as it's a cleaner install

[captain-codpiece]

When I was having my servo issue I chucked all my 27mhz stuff and bought a second hand 40mhz setup, but the receiver was just a standard one again. I then tried a mates Novak Receiver and it worked straight away. So I kinda borrowed it from him(thanks Paul), then bought one myself. I haven't had any issues since and haven't had to run any extra stuff. It was a 40mhz Novak XXL. Only issue is I don't think they make it anymore, so I scoured flea-bay and got one for £20.

[KennyClark]

Had a similar problem with a bluebird servo.

A capacitor plugged into the receiver cleared it.

[mikeyscott]

Originally Posted by KennyClark

Had a similar problem with a bluebird servo.

A capacitor plugged into the receiver cleared it.

Which one did you purchase?