Weird Servo Issue

[robertjpjr]

Just bought a solar servo d772. Seemed to work fine and I waterproofed it by coating the board in dielectric grease. Now after a run or two the servo cuts out on "idle" with no input left or right the servo "shuts off". If I turn the wheel, the servo reengages. Sometimes after a twist or two. Or even a manual push of the wheel.
Its definitely the servo. I scooped out all the grease but its still happening.
Ideas?
Seems like the board or perhaps the pot?

[Meatwad]

What's your setup? Do you have a bec?

[robertjpjr]

Holmes Hobbies BXRL WP - castle BEC at 7.2 Servo is good for 8.4 - Flysky 3ch RX

I've Tested each component. Its definitely the servo.

[TacoCrawler]

die-electric grease doesn't really protect the board
from moisture...
it simply displaces or repels water from itself
and is non conductive.

Meaning: if an interior volume is filled up with the grease...
there is little room left for water to intrude or reside.

Problem is.... it cannot be packed tight enough
to fill all the crevices on a circuit board.

I recommend a conformal coating...
or other water proofing method such as "Never-Wet"

I prefer the "Never-Wet" coating on PC boards...
primarily because it works...
but also because it will still allow a programing light
to show thru. (helpful for many ESC or other boards using a visual light diode)

Conformal coatings and say plastic dip may seal things up...
but they will also block any emitting lights. (not an issue with servos)

I realize the "Never-Wet" mfg'r does not warranty/recommend their product
for electronics.
But it does work if applied properly.

[robertjpjr]

Ya thanks. I've tried a couple different methods. The servo hasn't seen water yet. So its not water logged or anything. I will have to get conformal coating. Keep putting it off.

[TacoCrawler]

I cannot say exactly what may have occurred with your servo...
but it is likely moisture/condensation related...
Or the die-electric grease may be partially at fault if it melted
on the pc board.
Could be there was enough moisture in that grease to cause issue !? :dunno:

I applied "Never-Wet" on all three of my D772's
circuit boards...
then packed the area around the output shaft with grease.
also put a shock O-ring on the servo's output shaft.
( ^ sandwiched between the servo case and servo horn)
( * some grease was applied to that O-ring as well)
Lastly... I spray coated the whole body of the servo
with spray on plastic dip.
(well... not the upper side where the output shaft resides, that was left raw)

I have not had any issues with any of them since doing that.

Good thing it was a cheap servo to buy... and destroy

Now you get to buy another

Oh... almost forgot to ask...
How many volts are supplied to the servo ?

Just asking 'cause if it's under powered... it can glitch or operate strangely at times.

[robertjpjr]

Originally Posted by TacoCrawler

I cannot say exactly what may have occurred with your servo...
but it is likely moisture/condensation related...
Or the die-electric grease may be partially at fault if it melted
on the pc board.
Could be there was enough moisture in that grease to cause issue !? :dunno:

I applied "Never-Wet" on all three of my D772's
circuit boards...
then packed the area around the output shaft with grease.
also put a shock O-ring on the servo's output shaft.
( ^ sandwiched between the servo case and servo horn)
( * some grease was applied to that O-ring as well)
Lastly... I spray coated the whole body of the servo
with spray on plastic dip.
(well... not the upper side where the output shaft resides, that was left raw)

I have not had any issues with any of them since doing that.

Good thing it was a cheap servo to buy... and destroy

Now buy another

Thanks for your advice. I've done various waterproofing techniques.
The servo works fine. Just goes into sleep mode or something when there's no input. The servo whine stops, but if you listen closely you can hear it super faint. So maybe the chip is telling the motor to stop spinning. I've got spares. I buy these servos for all my rigs. This is the first one I'd consider DOA. Even though it still works. I'll run it till it smokes.
These servos are so tough. Get them wet? Crack it open, dry, good as new.
Havent had any problems with any of the dozen or so I've had. Except this guy.
May just use it for parts eventually.

[robertjpjr]

Bec is putting out 7.2 volts. I think I tried the servo straight off the ESC too. Can't remember, long night.