Digital Servo Singing

[Ron Van Putte]

On Nov 17, 2003, at 5:02 PM, michael Medlin wrote:

> I have been running the same set of Hitec digitals for two seasons 
> now, and
> they have made that singing sound from day one, but it has never had 
> any
> negative effect. As far as power consumption, they draw no more than 
> the
> coreless servos I replaced
> . The only problem I have had is sloppy gear train after a while, 
> which I
> guess is normal with metal gears.

It is a good idea to make sure that there's enough grease on the metal 
gears.  I have found some which had plenty of grease, some with a tiny 
bit of grease and some with NONE at all.  The wear goes up 
exponentially in the absence of grease.

Ron Van Putte

> ----- Original Message -----
> From: "george kennie" <geobet at gis.net>
> To: <discussion at nsrca.org>
> Sent: Monday, November 17, 2003 12:54 PM
> Subject: Re: Digital Servo Singing
>
>
>> Keith,
>> Save yourself a lot of work! I was at my local field yesterday and 
>> there
> was an
>> IMAC guy there with an Extra 330 with all Hitec servos and that thing 
>> was
> making
>> the Halelujia chorus big time, and was audible from a significant 
>> distance
> from
>> the airplane because it's quite loud . If guys have never heard this
> before they
>> can only guess about what you're talking about. This VERY high pitched
> whine, as
>> opposed to the normal servo BUZZ, I was told, has something to do 
>> with the
> type
>> of amplifier the servo employs and is nothing to be concerned with,
> however, I
>> find the noise to be a little disconcerting.The pilot told me that he 
>> has
> a full
>> season on them without problems.
>> Good Luck,
>> Georgie
>>
>>
>> Keith Hoard wrote:
>>
>>> Thanks, Troy.. . . I'll go out and try your suggestions!!
>>>
>>> Keith L. Hoard
>>> Cordova, TN
>>> khoard at midsouth.rr.com
>>>
>>> ----- Original Message -----
>>> From: "Troy Newman" <troy_newman at msn.com>
>>> To: <discussion at nsrca.org>
>>> Sent: Sunday, November 16, 2003 10:39 PM
>>> Subject: Re: Digital Servo Singing
>>>
>>>> That's right H9 makes a new little ammeter deal that goes inline to
> check
>>>> that sort of thing. I don't have one yet...but I saw them and may 
>>>> have
> get
>>>> Jenny to loosen the purse strings a little....They are only like
> $35-40
>>>>
>>>> This little tool will tell us a bunch about our radio
> gear....Especially
>>> in
>>>> setting up the big models with multiple servos on each surface....
>>>>
>>>> You can use it between battery and RX to see what the current draw 
>>>> on
> the
>>>> enitre system is...And running the motor compare the difference 
>>>> under
>>>> vibration compared to no motor....And then try different servos to 
>>>> see
> if
>>>> this servo or that servo has a higher battery drain....This could 
>>>> also
>>> help
>>>> diagnose problems with a servos and help find worn pots too...as the
>>> servos
>>>> will hunt more and draw more power as the pots wear.
>>>>
>>>> Pretty cool little item.
>>>>
>>>>
>>>> TN
>>>>
>>>>
>>>>> From: davel322 at comcast.net
>>>>> Reply-To: discussion at nsrca.org
>>>>> To: discussion at nsrca.org
>>>>> Subject: Re: Digital Servo Singing
>>>>> Date: Mon, 17 Nov 2003 04:11:11 +0000
>>>>>
>>>>> ....and......
>>>>>
>>>>> if you can put an ammeter inline, see what the servo is drawing at
> idle
>>>>> (with nothing attached) and compared the idle current to other
> similar
>>>>> servos - if it is substantially different, change it.  I am not too
>>>>> familiar with the Hitecs, so I can't volunteer specific numbers.
>>>>>
>>>>> Dave Lockhart
>>>>> DaveL322 at comcast.net.
>>>>>> digital servos are very good at finding center...and holding it
>>>>>> there....This takes some power to do it...The hum that you hear
> with
>>>>>> digitals is common....
>>>>>>
>>>>>> I would suspect its OK...I don't know much about the Hitecs...but
> try
>>> a
>>>>>> little subtrim or trim and you should be able to get the servo to
>>>>>> stop.....Usually the weight of the surface is enough to get a
> little
>>>>> whine
>>>>>> out a digital servo. But with all linkage disconnected...I would
> think
>>>>> you
>>>>>> should be able to get it stop.
>>>>>>
>>>>>> I would not be overly concerned...maybe the gear train is a little
> too
>>>>> tight
>>>>>> or another option is perhaps when you have bolted down in the
> servo
>>>>> mounts
>>>>>> its not straight and the case is slightly tweaked....I know this
>>> sounds
>>>>>> funny but I have seen it happen. Loosen the servo mounting screw a
>>>>> little
>>>>>> and see if it stops...then slowly tighten in an opposing
>>> pattern...till
>>>>> the
>>>>>> servo is snug. DO this while the radio gear is turned on and you
> can
>>>>> find
>>>>>> out if it stops the buzzzzzzz
>>>>>>
>>>>>
>>>>>> Another option...perhaps you Pot is worn an is send a changing
>>>>> signal....Say
>>>>>> step 1024 and 1023 and the and the servo is fighting itself to get
> in
>>>>>> between...to check for this try another channel on the
> RX...usually a
>>>>>> throttle...as the throttle TX pot doesn't get worn at center....
>>>>>>
>>>>>> But I think you may be OK...these are just precautions...and I bet
>>>>> you'll
>>>>>> find it....If it is one of these two little things...not too much
> to
>>>>> worry
>>>>>> about.
>>>>>>
>>>>>> TX pots can be serviced...and the servo mounting twist can be
> fixed
>>>>> easy....
>>>>>>
>>>>>>
>>>>>>> From: "Keith Hoard" <khoard at midsouth.rr.com>
>>>>>>> Reply-To: discussion at nsrca.org
>>>>>>> To: "NSRCA Mailing List" <discussion at nsrca.org>
>>>>>>> Subject: Digital Servo Singing
>>>>>>> Date: Sun, 16 Nov 2003 21:39:39 -0600
>>>>>>>
>>>>>>> Guys,
>>>>>>>
>>>>>>>     I've just installed my first digital servos. . . Hitec's.
> One
>>> of
>>>>> them
>>>>>>> "sings" continuously even when it is not under any load.  Is this
>>>>> normal??
>>>>>>> I'm using a 4-cell 1200Mah Nicd pack (if that makes a
> difference).
>>>>>>> Thanks!!
>>>>>>>
>>>>>>>
>>>>>>> Keith L. Hoard
>>>>>
>>>>>>> Cordova, TN
>>>>>>> khoard at midsouth.rr.com
>>>>>>>
>>>>>>
>>>>>> _________________________________________________________________
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>>>>
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