Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: Norman Castle on December 21, 2015, 04:10:53 pm

Title: Hitec servos
Post by: Norman Castle on December 21, 2015, 04:10:53 pm
Up until now I've always used either TowerPro or HobbyKing servos, with which I've never had any problems, but I was recently persuaded to support the LMS by buying a standard servo from it.  I came home with the recommended Hitec HS311, which at first impressed because it's noticeably quieter than I'm used to.

However, I now find that it has a nervous tic when I take my finger off the stick which is controlling it and it centres itself.  It seems to have difficulty deciding whether it's in the right place, so every now and then it gives a very slight twitch one way, then sooner or later a twitch back.   In other words, it moves erratically about the neutral position, apparently at random.

I stress that I'm talking here about a very slight movement, but even if it's not readily visible, the servo can be heard and felt doing its own small-scale thing.

Now, if it didn't have this habit I'd be happy with it despite it costing me roughly twice what I'm used to paying for a servo, but what I need to know is - is this sort of thing par for the course with Hitec servos?  BTW I'm as sure as I can be that it's a genuine one.
Title: Re: Hitec servos
Post by: malcolmfrary on December 22, 2015, 10:17:40 am
I'm pretty sure that this is not normal - the servo can only do as it is told.
BUT if there is any instability in either the received signal resulting in changes to the output of the receiver or variations in the voltage that the servo is getting, the servo will hunt for its new required position.  Its one of those times when a servo tester is worth having, if only to help figure out whether the problem is the servo or something else.
Title: Re: Hitec servos
Post by: Norman Castle on December 22, 2015, 12:59:19 pm
...Its one of those times when a servo tester is worth having, if only to help figure out whether the problem is the servo or something else.

Sorry Malcolm, I should have added that it also does it when connected to a servo tester and "neutral" is selected.
Title: Re: Hitec servos
Post by: essex2visuvesi on December 22, 2015, 01:36:31 pm
Sounds like it could be a dirty Potentiometer in the servo
Title: Re: Hitec servos
Post by: Subculture on December 22, 2015, 02:24:36 pm
Just because you pay twice the price, it doesn't mean you get twice the quality.

Take it back and ask for a replacment.
Title: Re: Hitec servos
Post by: Norman Castle on December 22, 2015, 03:56:30 pm
Just because you pay twice the price, it doesn't mean you get twice the quality.

Indeed!  Oh well, lesson learned ...

Thanks chaps.
Title: Re: Hitec servos
Post by: richald on December 22, 2015, 05:56:10 pm
came across this... looking for Hitec Servo / LMS comments on Google

http://www.rcmf.co.uk/4um/transmitters-receivers-and-servo-forum/jittering-hitec-servos/10/?imode (http://www.rcmf.co.uk/4um/transmitters-receivers-and-servo-forum/jittering-hitec-servos/10/?imode)

I wasn't sure what LMS meant (I don't recall seeing it before) - I assume it is Local Model Shop ?

Richard
Title: Re: Hitec servos
Post by: malcolmfrary on December 23, 2015, 10:31:15 am
Sorry Malcolm, I should have added that it also does it when connected to a servo tester and "neutral" is selected.
That's why every home should have a servo tester - it shows up faulty servos without all the head scratching that comes from using other signal sources and power supplies.  My current one is a fleabay special that lets you plug up to 3 in at once.  This is handy for just this situation.  Plug in a known good one and the one in question and see what happens.
Title: Re: Hitec servos
Post by: sparkey on December 23, 2015, 11:29:07 am
 >>:-( There has been a lot of fake Hitec servos out there,if I remember right the fake ones don't have the metal ring on the fixing holes,don't worry I bought a couple of the fake ones,one went up in a puff of smoke and the other twitched all the time so I didn't use it,I bought them from a stall at a show some time ago and it was not till later that I heard of the fakes in a article in a mag.perhaps someone remembers that article and can tell you more.......Ray. >>:-(
Title: Re: Hitec servos
Post by: tigertiger on December 23, 2015, 03:15:30 pm
I have bought several Hitec servos, for hight torque use. Never had a problem, found them great and a fraction of the price of Futaba for the same performance. They are just a wee bit bigger.


I got mine from Als Hobbies on line.
Title: Re: Hitec servos
Post by: inertia on December 23, 2015, 03:39:36 pm
Just last week I checked over a full model boat installation which included a sound system, power distribution board, P94 dual ESC, two Speed 700 motors and a rudder servo. Without the servo everything worked fine, but with the servo connected the sound system cut out with even a tiny amount of steering command. The faulty servo was one of the brand that Norman usually uses, and all was hunky-dory when it was replaced. I've also had a digital winch servo with the same manufacturer's label which just sat immobile and looked insolently at me, and another smaller type which trembled so much when powered up that I thought it had hypothermia! I can conclude only that those particular examples were duff because other people have no trouble with the type.

I've standardised on Hitec gear, including their servos, and I've never had a second's trouble with any of them - but I do buy mine from a recognised UK Hitec dealer (Steve Webb Models t/a Servo Shop).

Maybe there's a moral in there somewhere. Answers on the back of a £20 note please.

Dave M
Title: Re: Hitec servos
Post by: tigertiger on December 23, 2015, 03:54:26 pm
Sorry Dave, I've only got 9 bob notes  %%
Title: Re: Hitec servos
Post by: Norman Castle on December 23, 2015, 04:13:28 pm
Sorry Dave, I've only got 9 bob notes  %%

I can change those for you.  Three threes or a seven and a two.  Up to you! 8)
Title: Re: Hitec servos
Post by: derekwarner on December 23, 2015, 09:23:48 pm
DM....what has this Michael to do with this brand of R/C equipment?..............or is it just a co-incidence and that is just the forerunner of a servo to his lower right on the podium?....... Derek  :o
Title: Re: Hitec servos
Post by: inertia on December 23, 2015, 11:11:43 pm
DM....what has this Michael to do with this brand of R/C equipment?..............or is it just a co-incidence and that is just the forerunner of a servo to his lower right on the podium?....... Derek  :o
Sorry, Derek, but that question's beyond my capacity to answer. Looks a bit like a Wimshurst Machine to me, though. Probably isn't.
"Shocking!" (as James Bond said as he threw the electric fire into the bath...)
DM
Title: Re: Hitec servos
Post by: derekwarner on December 23, 2015, 11:35:19 pm
Possibly it was some sort of early spinning wheel device that Michael used to catch all of those unaccounted Farad's that were running amuck in his garden & electrical workshop?......

Come to think of it :o, I am not sure if he ever really confirmed the colour of his new invention  ....

These Hi-Tec components in question may need a few more Farad's thrown into their plastic cases  {-).........Derek
Title: Re: Hitec servos
Post by: inertia on December 24, 2015, 08:57:24 am
Possibly it was some sort of early spinning wheel device that Michael used to catch all of those unaccounted Farad's that were running amuck in his garden & electrical workshop?......

Come to think of it :o, I am not sure if he ever really confirmed the colour of his new invention  ....

These Hi-Tec components in question may need a few more Farad's thrown into their plastic cases  {-).........Derek
Derek
I have it on the very highest authority that Farads are green and don't have an apostrophe in the plural.
DM
Title: Re: Hitec servos
Post by: sparkey on December 24, 2015, 09:45:38 am
 {-) I heard that he kept them in a Faraday cage O0 {-)
Title: Re: Hitec servos
Post by: derekwarner on December 24, 2015, 11:00:05 am
 ;) mmmmmmmmmmmm...DM says....'have an apostrophe in the plural'  {-) ....well yes & no...my take on this is the confirmation that in OZ, usually there is more than one blo-fly just hanging about on the BBQ  <*<

So the answer must be blo-flyes .........accordingly a fly does not hover, so the movement of the pest must be flying....if this is not the case, should two blo-flies in the act of movement not be bol-flyers?......sorry....just your English language

Does this not hovering, but jittering movement not remind you the pest like Hi-Tec component...tis....sssss [plural] ..

Bring on the Mortein Aero-Gard ........... Derek