Re: Strange Servo Failure Mode, near end of travel (one direction only)

[Beav]

"Dan Asay" <danasay@cox.net> wrote in message
news:Dv6Cc.68$rh.24@okepread02...
> Thanks Beav,
>
> I always value your advice.

Thanks for that Dan.
>
> If I cannot narrow the scope of possible causes to an acceptable risk, I
> will be left with no choice but to "bin the servo".

The problem with servos is they REALLY should be considered as consumables.
They don't last forever and if you get a couple of seasons flying from a
set, you're ahead of the game. After that, I don't consider them worth even
looking at if they show any signs of "offness"


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[Dan Asay]

Now that I'm paying more attention to these consumables, I noticed my
elevator servo starting to shake today just around center position. I won't
be flying the rebuild until both cyclic servos are renewed. However, I will
take the old ones to work and look at them thoroughly with a microscope to
see if I can learn anything or if I can find a cracked solder joint that
might allow me to restore servo performance. If not, they're trash.

"Beav" <beavis.original@ntloxoworld.com> wrote in message
news:10dk1h7ciq7qj8c@news.supernews.com...
>
> "Dan Asay" <danasay@cox.net> wrote in message
> news:Dv6Cc.68$rh.24@okepread02...
> > Thanks Beav,
> >
> > I always value your advice.
>
> Thanks for that Dan.
> >
> > If I cannot narrow the scope of possible causes to an acceptable risk, I
> > will be left with no choice but to "bin the servo".
>
> The problem with servos is they REALLY should be considered as
consumables.
> They don't last forever and if you get a couple of seasons flying from a
> set, you're ahead of the game. After that, I don't consider them worth
even
> looking at if they show any signs of "offness"
>
>
> --
> Beav
>
>
> Please note my E-mail address is "beavis dot original at ntlworld dot com"
> (with the obvious changes)
>
> Beavisland now lives at
> www.beavisoriginal.co.uk
>
>

[Steve R.]

"S-Man" <w8an@NOSPAM.sbcglobal.net> wrote in message
news:0TqCc.797$e71.459@newssvr33.news.prodigy.com. ..
> Beav wrote:
> > The problem with servos is they REALLY should be considered as
consumables.
> > They don't last forever and if you get a couple of seasons flying from a
> > set, you're ahead of the game. After that, I don't consider them worth
even
> > looking at if they show any signs of "offness"
>
> Just *what* on a heli isn't a consumable?? I think I've replace all the
> parts on mine... no wait.. I haven't smashed the receiver yet... ;-)
>
> .S.

Uh-Oh, you just jinxed yourself on that one! :-o ;-)

Fly Safe,
Steve R.

[C W]

When servos were much more expensive in real terms in the 80's, I
regularly replaced feedback potentiometers.

However, Ripmax in the UK a couple of years ago started not to
want to sell `electronic' spares for servos - citing Health &
Safety issues. (and no doubt product liability creeps in as well)
- unless of course they repaired the servo. Not sure what their
current position is. Comment from Ripmax - if they read this -
would be useful.

But I really don't like the `consumable' culture - and I hate
binnining an expensive servo for the sake of a feedback
potentiometer.

And the `'neutral' position of the servo is always where the
potentiometer track wears most ..... = the jitters around neutral.

CW


On Thu, 24 Jun 2004 02:19:41 GMT, S-Man
<w8an@NOSPAM.sbcglobal.net> wrote:

>Beav wrote:
>> The problem with servos is they REALLY should be considered as consumables.
>> They don't last forever and if you get a couple of seasons flying from a
>> set, you're ahead of the game. After that, I don't consider them worth even
>> looking at if they show any signs of "offness"
>
>Just *what* on a heli isn't a consumable?? I think I've replace all the
>parts on mine... no wait.. I haven't smashed the receiver yet... ;-)
>
>.S.

[Beav]

"S-Man" <w8an@NOSPAM.sbcglobal.net> wrote in message
news:0TqCc.797$e71.459@newssvr33.news.prodigy.com. ..
> Beav wrote:
> > The problem with servos is they REALLY should be considered as
consumables.
> > They don't last forever and if you get a couple of seasons flying from a
> > set, you're ahead of the game. After that, I don't consider them worth
even
> > looking at if they show any signs of "offness"
>
> Just *what* on a heli isn't a consumable?? I think I've replace all the
> parts on mine... no wait.. I haven't smashed the receiver yet... ;-)

Just the flyer and some of them are too:-)


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[Beav]

"Dan Asay" <danasay@cox.net> wrote in message
news:6WrCc.5743$Lh.850@okepread01...
> Now that I'm paying more attention to these consumables, I noticed my
> elevator servo starting to shake today just around center position. I
won't
> be flying the rebuild until both cyclic servos are renewed. However, I
will
> take the old ones to work and look at them thoroughly with a microscope to
> see if I can learn anything or if I can find a cracked solder joint that
> might allow me to restore servo performance. If not, they're trash.

You'll probably find the feedback pot track that the wipers run on to
give/take the signal is in need of cleaning and re-greasing (vaselining). If
that's all it takes to sort the servo, it's not a binnable item and this
sort of thing is WELL within the abilities of most modellers (or it WAS).


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[Dan Asay]

I thought that was oil from exhaust fumes. That was vaseline?

I placed several of my servos under a microscope today and learned a little.
I was about to post the results, but I'll edit the part about the oil and
then post it as a separate thread.

Thanks again.

Dan

"Beav" <beavis.original@ntloxoworld.com> wrote in message
news:10dluait4mr1c95@news.supernews.com...
>
> "Dan Asay" <danasay@cox.net> wrote in message
> news:6WrCc.5743$Lh.850@okepread01...
> > Now that I'm paying more attention to these consumables, I noticed my
> > elevator servo starting to shake today just around center position. I
> won't
> > be flying the rebuild until both cyclic servos are renewed. However, I
> will
> > take the old ones to work and look at them thoroughly with a microscope
to
> > see if I can learn anything or if I can find a cracked solder joint that
> > might allow me to restore servo performance. If not, they're trash.
>
> You'll probably find the feedback pot track that the wipers run on to
> give/take the signal is in need of cleaning and re-greasing (vaselining).
If
> that's all it takes to sort the servo, it's not a binnable item and this
> sort of thing is WELL within the abilities of most modellers (or it WAS).
>
>
> --
> Beav
>
>
> Please note my E-mail address is "beavis dot original at ntlworld dot com"
> (with the obvious changes)
>
> Beavisland now lives at
> www.beavisoriginal.co.uk
>
>

[Beav]

"Dan Asay" <danasay@cox.net> wrote in message
news:CZKCc.13420$Lh.3027@okepread01...
> I thought that was oil from exhaust fumes. That was vaseline?

It's VERY unlikely to be oil from the flying. More likely to be whatever the
manufacturer put in their when the servos were made. The tracks need
SOMETHING to lubricate them and vaseline has worked for years.
>
> I placed several of my servos under a microscope today and learned a
little.
> I was about to post the results, but I'll edit the part about the oil and
> then post it as a separate thread.

I got it about a minute ago:-)


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk