My HSG5084 servo fried... Why???

[347mont]

Boy make a grown man cry or what. So I put on some new Gaui blades and take my heli out

the front to test them and my newly rebuilt 300x. I was just hovering around poping it up and

did a few piros. 2.5 minutes into the flight the heli was looking unstable so I start bringing it

down and when it was about 1.5ft off the ground it got a sort of TBE. I had no choice but to hit TH

which resulted in splitting one of my brand new Gaui's enlarging the hole in my Fusuno canopy

where it mounts and chipping the paint of my front bumper of my car. I'm pretty sure thats it

but haven't thoroughly checked the heli out yet. Anyways I was inspecting the damage and the

heli was still powered up and I noticed smoke coming from the tail servo so I immediately

unplugged the battery and of course the servo was hot. I'm running the Hitec HSG5084 and also

CC Ice Lite 50 ESC and Scorpion 2213-14 motor. Does anyone know what would of caused this?

I had the D menu point in Setup menu on red or 270Hz. Could that be the cause or would it

be a setup I had in the ESC that caused it. I'm still learning the more technical side of the hobby

so bare with me. All I know I was queezy in the stomach when a test flight under 3 minutes cost

me a brand new set of gaui blades a decent tail servo and a damaged good looking canopy.

So those comrades that might know what causes servos to fry please let me know.

OK I'm going away to have a cry and hopefully we can get to the bottm of it.

[GSPI]

What is your BEC voltage?

[347mont]

Its set to 6V. That sounds bad,

Should it be 5V or lower than 6V.

[GSPI]

Yes I was afraid of that. There has been some confusion with the documentation from HiTec as to what it's rated for and from what I've seen it's supposed to be 4.8v with a 333hz setting. Others using regular single axis gyros have had similar issues with this servo too because the documentation is poor.

[spykez]

If the servo was binding it could have burnt itself out, but whether this happened on the ground or in the air, I have no clue to be honest. Chicken or egg I dunno.

What I do in a crash is as soon as I deem it safe to approach, I immediately unplug the lipo to avoid burning any servos out (or anything else for that matter). Then I look for the damage.

I have had no issue with 5084's - my 450 3D with a quark still flies it, initially with the stock ESC set at 6V then 5,5 with the YEP 45A.

[347mont]

Thanks GSPI. What I've got to do is learn more about the technicality of electonics. Does this

mean the servos were receiving up to 6v at times and that over heated/ fried my HSG5084.

Man I've fully bombed this bird got every upgrade on it and ironicly its making its way back to

stock lol. I snapped the carbon boom last week so back to stock there and now I've put the

stock tail servo back on and damaged 1 of the blades.

[347mont]

Spykes, to be honest last week when I test flew, about 10 packs all up, I did notice the tail servo

rather hot on some of the flights it had. On others it seemed good. I set my end points so I don't

think binding would be the issue. Only got into the hobby August 2012 and started on a 120sr

so I've got a lot to learn still. Oops I lie I started on a Double horse 9101 , hey but it got me

addicted to this hobby and I'm 38yo. Man I should really be dumping all this cash into my car (real)

I'm building.

[spykez]

Originally Posted by 347mont

....Does this

mean the servos were receiving up to 6v at times and that over heated/ fried my HSG5084.
...

Possibly... I remember there was some debate a while back on what voltage this servo is actually rated for. But .. fwiw...

http://www.hitecrcd.com/products/ser...sg-5084mg.html

So I just flipped the switch on the 4503D ESC/BEC to 6V and flew the thing. Granted now I use a YGE clone on the thing now - I might be lucky or you might just be unlucky.

GSPI is way more electronically minded than me, but sometimes with these things, my take on it is they work or they don't, but if they don't generally you find out about it pretty promptly. I had a 5065 burn out on me once and the thing didn't even fly (I had just put the thing BRAND NEW on my 450 and was doing setup). I just chalked that one up to being faulty.

I don't know all that much more than you to be honest, but one little tip, I believe I owe this to Finless, make sure the tail action is really smooth. Don't ream or sand anything to sloppiness but when tugging at the pushrod disconnected from the servo you should really be able to move the tail slider effortlessly as a general guide I would think.

[GSPI]

The main thing with these devices are as you said spykez, you get lucky sometimes. The specification range on some of these items (anything electronic actually) have ranges of tolerance (not really taking shoddy workmanship or a problematic design into account). Some fall one way, others fall the other. When the load on the heli is less, there is more voltage level available. However, during these times when the system is put under load the voltage may drop but not enough and there would be amps involved too which may overload the servo. Others are far more analytical and knowledgeable than I when it comes to electronics but my mechanical experience tells me the less you load the system the better off you are. Making sure that all control linkages and surfaces operate smoothly by hand is a very good indicator of what the load the servo is experiencing. Any seemingly stiff or snugness of the control, the more load the servo is taking and will demand more energy to perform it's actions. More energy relates to more heat when it's not used efficiently. So then comes the overheating and possible smoke. Chain reaction to the specification being one way or the other and falling into a danger zone of operation.... then the crash or emergency landing.

Good luck and happy flying!

[ahahn]

FWIW,
After reading about tail servos burning out (on every sort of heli), that's one thing I always check out on the first few flights, and every-so-often---simply touch the tail servo to make sure it isn't hot.

If it feels warm, then it's time to fix the problem. The problem can be vibration related (gyro/fbl) is making the servo work too hard, or the load--something is binding in the tail or the load is just too high for that servo. High voltage and/or high update rate, coupled with something going south in the tail mechanics is probably a bad combo.

I note that my DS76T running stock on the 300X has never felt warm.

The Hitec 5084 has always had a uncertainty associated with its voltage spec. My guess is that it isn't just the voltage, but also the load that explains why some have no issues with 6V on it, and some are burning up.

These servos are not made to run hot, and if they are, then somethings up. Better check out what it is, or suffer the consequences

[xpantz]

I've been running 5084MG on the tail @ 6v /333hz for some time.

Performance wise lower voltage and frequency would be fine for most people... I don't seem to notice a difference anyway.

Hitec website seems clear that 6v is supported but does not give frequency for Beastx setup.

Beastx says 333hz on the tail but does not mention voltage.

So I'll just run 6v / 333hz untill it blows up.

I put the IR gauge on my servos frequently and they don't get warm at all.... ambient... pretty much.

[EDIT] Took this heli out this morning and gave it a thrashing. I was as mean to the tail servo as my skill level will allow... locked in prios... one way and the other. When I got it back on the ground I held the servo left then right... nothing.

I can't cause a rise in temperature of more than a couple of degrees.

[347mont]

It's just one of those things I guess. I've taken

the tail servo pushrod off and played with the pitch slider

and it was nice and free, slid nicely. Splitting

one of my rotor blades is getting to me when I

think about it. Doah! One thing I've learnt if something

doesn't seem right stop and inspect. I should of done that

last week when I notice it getting hot. Double doah

[xpantz]

I've been going through all the 5084mg scary threads I can find.

Every time somebody emails Hitec customer service they seem to say 6v is fine.

As recently as November last year.

Hitec website still says 6v. You would think that if they had many problems at 6v then they might change that.

Suggest not listening to anecdotal evidence and asking Hitec support directly... they might even replace it for you.

service@hitecrcd.com

[347mont]

I sent HiTec a friendly email so I'll let you know what comes of it.

I've had others (Xtreme & Lynx) stand by their

products in the past so hopefully HiTec will be no different.

Cheers Wayne.

[Chavezpr@p]

What gyro gain % were you using? I found that the recommended 77% was a little high for the stock tail servo by about 5% or so, my stock tail was always running hot before then. Then when i switched to Hyperion ds11 tail i had to drop it down further to 68%. This is my experience others may differ. I also recommend running the servo endpoints setup whenever you change the tail servo (burnt out a stock tail from binding when i didn't do this ). Good luck with it!.

[xpantz]

Originally Posted by Chavezpr@p

What gyro gain % were you using? I found that the recommended 77% was a little high for the stock tail servo by about 5% or so, my stock tail was always running hot before then. Then when i switched to Hyperion ds11 tail i had to drop it down further to 68%. This is my experience others may differ. I also recommend running the servo endpoints setup whenever you change the tail servo (burnt out a stock tail from binding when i didn't do this ). Good luck with it!.

I have different Gyro for tail servo type and again for each head speed.

Align 425m
3100rpm = 38%
3250rpm = 31%

Hitec 5084mg
3150rpm = 50%
3400rpm = 51.5%

Does not make a lot of sense to me but those settings for each HS are where the tail shudders in tight turns or windy conditions stop.

I fly some aggressive moves at a particular HS and if I get a shudder I drop the Gyro 5... if the shudder goes away I sneak it back up till it appears again then drop back 1 or so.

There is no correct setting... just the right one.... and not higher than necessary.