Vibration or shakes? CHECK THIS!

[ChrisH]

Originally Posted by isogloss3d

Thanks for the tips Chris. I cleaned all 3 servos and the moderate shakes after 70 flights are now gone. The Aileron contacts were the dirtiest. Now that the major shakes are gone I'm noticing a very slight tail bob towards the last 3rd of my flight. Who knows, it could be something else entirely. Thanks again.

-Iso

E-Flite batteries?

Most likely low headspeed. Same thing happens to larger helis -- low headspeed and stiff dampening (especially on FBL) leads to up-and-down tail bobble. Nothing you can really do if you're running 100% flat ... just lets you know it's almost time to land

[AcidDrink]

Originally Posted by Finless

Cool tip Chris! Mind if I do a video on how to do it sometime later?

Bob

Thanks Chris and Bob. I haven't tried it yet, but I am 99% sure it will sort the problem I have (really bad vibes starting around 3 minute of flight)

p.s. do you think I can use aftershave to clean it?

[Heli-Yeah!]

I have had the same build-up on my mSR servos before, and have had to do the same cleaning as mentioned (just be careful that when your cleaning the sweeps to wipe with the direction they run, otherwise you may damage them, or push fibers between the fingers). I think a lot of the dust can be attributed to the CF main shaft. On the mSR there was considerably more wear on the shaft due to the free floating flybar, but CF dust will always be present as long as we are using it as a main shaft material. Maybe a aluminum shaft could minimize the amount of debris.

[UKBananas]

Would this work?

http://www.horizonhobby.com/Products...rodID=BAC99981

[ChrisH]

Originally Posted by UKBananas

Would this work?

http://www.horizonhobby.com/Products...rodID=BAC99981

Maybe, but it looks like it's "temporarily out of production"

[tracknoob]

Originally Posted by ChrisH

Maybe, but it looks like it's "temporarily out of production"

I heard that the makers of "Tweek" aka "Stabilant 22" had some sort of patent infringement beef a long time ago with 'newcomers', so I wonder if they finally put the legal wolves onto anyone trying to 'knock off' their supposedly proprietary stuff. I know I saw at least one other similar product a year or two ago, and when I went to look into it, it also had been 'discontinued'. As documented in a prior post, I happened to have been sampled some of the Stabilent 22, so I cleaned my tracks and applied some to my mcpx servos last night. This morning's flights all went great, but I can't say it really improved anything -- this is probably one of those 'time will tell' situations.

[UKBananas]

Going to try this stuff:

http://www.amazon.com/MG-Chemicals-4.../dp/B0047Y7VIO

[tracknoob]

Beofre anyone disassembles their servos, I would be sure I had a problem!

Please read my experience this morning, after cleaning and applying contact cleaner/lubricant last night. Could be coincidence, or my own efforts somehow screwing things up, but still, consider:
http://www.rcgroups.com/forums/showp...postcount=8563

[mejmea]

I've used this stuff on larger contacts, rotary pots etc. Spray on and then run the contacts back and forth a few times to clean.

http://www.radioshack.com/product/in...ductId=2103700

MSDS is here, says it is predominantly tetrafluroethane with a small percent white mineral oil. I'm not aware that either of these should cause a problem - there are plenty of plastics in tv and stereo tuners so I don't think materials compatibility is an issue.

http://www.radioshack.com/graphics/u...4315A_MSDS.pdf


I haven't looked close enough at how tight the servo "case" fits the board, might it be possible to spray a bit of something like this in without disassembly?

[ChrisH]

Originally Posted by tracknoob

Beofre anyone disassembles their servos, I would be sure I had a problem!

Please read my experience this morning, after cleaning and applying contact cleaner/lubricant last night. Could be coincidence, or my own efforts somehow screwing things up, but still, consider:
http://www.rcgroups.com/forums/showp...postcount=8563

I've taken mine apart multiple times now (all 3 to clean them, and one another time just to make the how-to in the beginning of this thread) with no problems.

Could your issue be related to your magical lube? I have had a couple EE friends say that cleaning the contacts and then leaving them DRY is best.

[UKBananas]

Originally Posted by ChrisH

I've taken mine apart multiple times now (all 3 to clean them, and one another time just to make the how-to in the beginning of this thread) with no problems.

Could your issue be related to your magical lube? I have had a couple EE friends say that cleaning the contacts and then leaving them DRY is best.

Magical lube? That made me laugh. I read an Amazon review earlier on a conductive lube, which stated they had to clean again (with contact cleaner) after applying the conductive lube to get things working, so this may indeed be something here.

[dbennettya]

You don't want anything conductive. The silver looking strip is a conductor and the black strip is a resistor. This forms a potentiometer for feedback to the servo electronics. A better solution would be for the substrate to be ceramic and then they could use better resistor material fired at a higher temperature. Unfortunately that would cost more.

YMMV, Don

Originally Posted by UKBananas

Magical lube? That made me laugh. I read an Amazon review earlier on a conductive lube, which stated they had to clean again (with contact cleaner) after applying the conductive lube to get things working, so this may indeed be something here.

[UKBananas]

Sounds good, so Tracknoob - get rid of that lubricant!!!

[outspaced]

Excellent. I just cleaned the tracks on the side servos with isopropyl and cotton buds, put the plain blades back on which are normally worst for the shakes, flew a battery and experienced exactly 0 shakes when normally it would shudder on a slow turn.

Thanks so much for posting!

[ChrisH]

I'm glad this helped some people. I was getting really frustrated when I couldn't fix my wobble!

[TheBum]

Originally Posted by ChrisH

I'm glad this helped some people. I was getting really frustrated when I couldn't fix my wobble!

Nobody can fix *your* wobble, Chris.

[tracknoob]

Originally Posted by UKBananas

Sounds good, so Tracknoob - get rid of that lubricant!!!

LOL

I told you guys I was gonna be a guinea pig for this, and by golly, I'm gonna stick to it!

If it had failed after my initial cleaning and lubing outright, I woulda cleaned it back off and reported back on that fact.

But since it did seem to pass initial functional check, and then worked for several flights, having the stuck servo the next day was certainly worrying, but others have had similar glitches without cleaning or lubing. So as long as it continues to work, I'm going to fly it and report back on what happens. (And meantime, also have another mcpx spare on the way, as well as servos heh heh.)

It seems to me, after more than 30 years of first hand experience with such things, that any time you take apart an electromechanical assembly, like a relay or a solenoid, or a servo, you are intrinsicly increasing the probability of failure due to your intervention. It could be you are wiping off 'good' carbon from the resistive slider as you try to gently clean... it could be you nudge a previously precision contact alignment... or you introduce contaminants... or moisture... or break a seal, and that allows oxidation to begin... or any number of other things... so being serious for a moment, I'm going to repeat my earlier advice, which may have ben missed:

If you are not actually experiencing issues that are directly attributable to the servo, then do not mess with it.

That said, if it is glitching, stuck, or otherwise failed you obviously lose nothing in trying to investigate what failed and whether you can perhaps get it going again (I almost said 'fix it' but that implies returning to a state of proper repair. See my earlier comment about somehow never being able to quite get *all* that magic smoke back in the tube once opened.)

Anyway, to address someone's concern about 'conductive' material, the first thing I asked about this Magic Goop when I first heard about it decades ago, to the rep trying to sell it to me was: "So this stuff goes right onto my gold PCB contacts, and then I slide it into the recepticle and it is not wiped away by the mating, correct?" "Correct." "So the electricity has to go through this stuff to get from male contact to female contact?" Correct" "So it's obviously conductive? " "Correct." "But you also claim it prevents cross talk and noise and is good to prevent static or stray signals from being picked up?" "Correct." So it's an insulator, with dielectric properties? " "Correct." The explanation is that the 'matrix' of material somehow gets polarized or aligned and when voltage is applied, it becomes conductive. but somehow, due to it's intrinsic properties, this stuff does NOT conduct to even fine pitch adjacent contacts, even if you slather it across the entire PCB.

Now, I was always a bit skeptical that this stuff could be so cleverly formulated that it 'knows' when to conduct and when to be an insulator, but I supposed that at the chemical/atomic level it is possible. Hey, I used to teach hole flow in solid state theory, so that pretty much gets you ready to entertain any theory, at least provisionally....

Anyhoo, suffice it to say, that while I remain skeptical, and somewhat concerned with that initial early glitch, that as long as it continues to work, I am going to leave the goop in, and see what happens! (But I *won't* be disassembling my brandy-new heli to apply it to those servos!)

[BPINE]

So what do you look for when it shakes new right out of the box?

[Oenta]

Well... i did clean my servos.. the random up/down servo jitter is gone!... But... still wobble!
Hmmmm... maybe it is my swashplate? my mainshaft doesnt seems to be bent.. my feathering shaft also.. i have some bites in my blades.. but nothing major.

i dont have a clue..

did all the other preflightchecks also...

[mejmea]

Originally Posted by BPINE

So what do you look for when it shakes new right out of the box?

There are a few threads going in the mCPX forum with suggestions including these:

https://www.helifreak.com/showthread.php?t=288652

https://www.helifreak.com/showthread.php?t=287334

Some basic things to check are that the main gear is oriented properly (i.e. not spun on the shaft, the flat spots should line up), the main gear is pushed all of the way up on the main shaft (NO vertical play in the main shaft), and that te retaining nuts on the servos are not backed off.

I had a relatively light crash into grass from 6-10 inches that spun the main gear on the shaft and before I figured that out I had intermittent shakes as I was hovering. Once I fixed that it went away.

I would search the mCPX forum for additional vibration related threads and you'll likely find a lot of information. It would also be helpful to have a more detailed description of the symptoms you are seeing and when they occur.