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Model Rectifier Corp . PowerHelis . JR-Spektrum

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Radio - Servo - Gyro - Gov - Batt > BLS451 failures?
 
 
Todd74
Heliman
Location: Prospect, PA

I just had one of these fail on me today. Bought brand new, only about 10 flights. Luckily, it happened on the bench, not in the air. I just powered up the electronics on my N9 to do some checks and the one cyclic servo just went nuts. Running on a 5 cell NiCad.

Just wondering if anyone else has seen any reliability issues with this servo.

Thanks,
Todd
06-24-2008 12:46 AM
 
 
Rymps
Senior Heliman
Location: Windsor CO and Indy

I have 6 of these in my fleet, and no problems. Sorry to hear it.
06-24-2008 01:21 AM
 
 
HelividD
Senior Heliman
Location: Auburn Hills, MI, USA

Not at all here. I have 3 machines with them in them on CCPM(50 sized machines). I am running Lipo's though regulated. No issues thus far and I have on one quite a few flights. On the other about 20 and the last and new one about now, about 4 flights.. No issues at all.

Sorry about the loss of the servo.. Bummer.. But definately good it didn't happen in the air...

D

Man.... I had no idea what an addiction this was going to be.....
06-24-2008 07:56 AM
 
 
bkervaski
Key Veteran
Location: Birmingham, AL, USA

I have about 15 of these in used, no problems, best servo I ever used. Sorry to hear about your troubles.

... will work for fuel ... Bill
06-24-2008 01:55 PM
HOMEPAGE  
 
 
Todd74
Heliman
Location: Prospect, PA

Oh well, I guess it's just my luck. I'm certain there is nothing wrong with my installation - been doing this awhile....

I pulled the servo and checked it with a different radio and reciever - same thing, so it's definitely bad.

Off to Hobby Services it goes - at least it's still under warranty.

Thanks,
Todd
06-24-2008 02:34 PM
 
 
helimatt
Elite Veteran
Location: Lafayette, IN

A little more info..

There were discussions about BLS451 failures a short while ago, here's a link:

http://runryder.net/helicopter/t403687p1/

Some had experienced early failures or odd behaviour from these servos, and then the Futaba rep came on and stated that they were not for Heli use... I don't know exactly where it all ended.

I'd get in touch with Futaba and see where they stand, and of course have them replace that servo that's acting up.

I've no skin in the game, just relating what's been done so far.

Never, ever, ever, ever give up.
06-24-2008 04:01 PM
 
 
Dr.Ben
Elite Veteran
Location: Richmond, VA, USA

Todd,

HS will warranty the servo. There are no inherent reliability issues in any application. Unfortunately, you had one of the rare ones that puked. They'll make it right.

Ben Minor
06-24-2008 05:53 PM
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

I always say, there's two times when electronics are most likely to fail...

1 - After a crash.
2 - Out of the Box.

They can't bench test every production servo. Here's a tip for anyone about to install a new servo in any aircraft: Get a servo driver capable of automatically cycling the servo. I have both the HiTec Servo Programmer/driver and the Bantam Heli Master. Either of these units will cycle a servo at various speeds. When I get a new servo, I stick it on one of this dudes, and let her run for a couple minutes. This makes sure the pot wears in nicely, the motor is reliable, and the servo amp board is capable of sustained current shifts.
06-24-2008 07:31 PM
 
 
Ken Filloon
Senior Heliman
Location: Highland, Michigan

Erichf
Thats the best advice I,ve heard. I just had a new S9155 take out my Raptor 90 on the servo's 3rd flight. Suuuuuucks.
06-24-2008 08:41 PM
 
 
Todd74
Heliman
Location: Prospect, PA

Erichf,
What you say is probably true most of the time I would agree, but this particular servo had 10 flights on it, not to mention quite a bit of bench time during set up, so it was well beyond the point where I would call it "out of the box". I usually do work new servos on the bench quite a bit before trusting them in the air like you suggest.

It terrifies me to think that this thing could have failed in flight - it was just pure luck that it happened the way it did. If this servo had 300 flights on it (and a couple of crashes) then I would not be surprised by a failure, but I usually put a lot of trust in brand new high end servos. Not anymore, I guess.

Thanks,
Todd
06-24-2008 08:47 PM
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Quote 
It terrifies me to think that this thing could have failed in flight

Tell me about it. My biggest concern when flying my Caliber 90 is electronics. I even went so far at one time to install dual switches and batteries, however charging was a real pain. So, I just went with my trusted MPI regulator and a new Spektrum 6000 Lipo receiver pack. It's a triple redundant pack (2S3P). It all still goes through one switch though, a JR Super Duty switch. I may try one of the MPI failsafe switches one day.
06-24-2008 09:16 PM
 
 
Four Stroker
Veteran
Location: Atlanta

I use the Tom Dooley approach and cycle servos for one hour before putting them in the heli. Then they get some more use in setup. Stalling servos can lead to sudden death.
06-24-2008 10:28 PM
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Quote 
Stalling servos can lead to sudden death.

Who said anything about stalling servos?
06-24-2008 10:48 PM
 
 
HelividD
Senior Heliman
Location: Auburn Hills, MI, USA

Erich, I have the heli master. I am wondering exactly what you do to test them. I mostly use the heli tach and haven't been able to use able to use alot of the other functions because for once I don't fully understand them. I want to use the servo tester and I got one and made it move back and forth. Is that what your talking about?

Sorry to hijack, but I was curious..

Man.... I had no idea what an addiction this was going to be.....
06-24-2008 11:28 PM
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Yeah, you can exercise a servo while also varying the cycle speed. The servo tester is good for centering servos before you even turn your radio on. I used mine to mechanically setup a CCPM bird for a buddy, and I never even turned the transmitter on. You can use it to find the mechanical and electrical limits of the servo, and choose arm lengths as appropriate.

For a new servo, make sure you have a full charge in the heli-master. Plug the servo in and press Function until "Servo Tester" is displayed. Then, press the Enter button, and you will see Man displayed next to the Amp indication (yes, this magic box displays amperage drawn by the servo). Using the Dec/Inc buttons will change the pulse output in .001 sec increments. L means low, and N means Neutral, and H means high. To activate the auto cycle, press the Enter button again once. Now you see an A in the upper left and 50% next to the Ammeter. Prss either the Dec or Inc button to start the cycler. Pressing and holding the Inc/Dec buttons adjusts the cycle speed. Increase it so that the servo reaches it's endpoints, but at the fastest cycle speed. For a tail servo, you may be able to max it out. I let it sit doing this for about 3-5 minutes, monitoring the servo temperature by feel, and noting the amperage. If the servo is disconnected from any links, it should remain around 0.1 Amp. If you want to check the health of an old servo, the ammeter is useful. You can partly stall the servo manually and monitor the ammperage. The Ammeter will also show if your binding a servo when installed in an aircraft.



On the flip side, you can plug the Heli-Master into your receiver and look at the pulse output. This is a great way to make sure you don't have some undesired mixes active in the radio, or to check the calibration of your TX sticks. It can also be used to look for dirty PWM outputs from receivers, gyros, or governors. I found a guy's new 401 bad with this feature. He was going to replace the servo first, until I put my HeliMaster on the gyro first. The PWM output was all over the place (1480-1550). This went to prove my earlier point (bad gyro out of the box).

I haven't used the built in Watt meter yet, though.
06-24-2008 11:43 PM
 
 
HelividD
Senior Heliman
Location: Auburn Hills, MI, USA

Ok, I am going to PM you if you don't mind. I need some help understanding and performing some things with it. Cool?

LOL, I saw you edited the post. I need to grab my tester and a servo...LOL

Man.... I had no idea what an addiction this was going to be.....
06-24-2008 11:48 PM
 
 
HelividD
Senior Heliman
Location: Auburn Hills, MI, USA

Ok, awesome. On a JR 821 I gt 899-1500-2101 for L,N,H. For the cycling I got up to 28% for the full travel but the A fluctuated between .1 and .3 is this ok?

Also, for the pulses on the reciever, how do you do that?

I know I am going to find setting up a machine now and finding the neutral great to say the least. I am sure that will save a ton of time!

Thanks man!

Man.... I had no idea what an addiction this was going to be.....
06-25-2008 12:06 AM
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Yeah, you will see an amp spike as much as 0.3A during the servo reversal, depending on the mass of the servo motor and gear train. Coreless servos have a smaller amp spike than cored motor servos like your 821, as their armature mass is less.

To measure the receiver pulse output, just press Function until "Measure Pulse" is displayed, then press Enter. Using a male to male servo lead, connect the Heli Master to any receiver output. The actual PWM output will be displayed in microseconds. So, if you have no mixes active in your radio, and all trims and subtrims are zero, you should have 1500 displayed. Now, some systems actually center on 1520, so bear that in mind. When checking a gyro output, make sure the gyro isn't getting moved while taking a reading. If the gyro is good, you will see a steady PWM output. In the case of my buddy's gyro, it was rapidly dancing between 1480 and 1550 uS, with no motion applied to the gyro. This was a gyro right out of the box and just installed on the heli.
06-25-2008 12:54 AM
 
 
hootowl
Elite Veteran
Location: Garnet Valley, Pa.

No problems here. Have four on my Stratus.

"Any man who says he is an American, but something else also, isn't an American at all.
06-25-2008 01:03 AM
HOMEPAGE  
 
 
HelividD
Senior Heliman
Location: Auburn Hills, MI, USA

Wow! Thanks dude! You explained it much better than the manual. One thing that I did not know is exactly the measurements for say a "good" servo or gyro should be as a reference. Thanks a million! Now I feel like I can use this thing a bit more and make the money spent worth while! I created a little document with your instructions so I can add them to the manual as a tutorial.

D

Man.... I had no idea what an addiction this was going to be.....
06-25-2008 11:19 AM
 
 
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Radio - Servo - Gyro - Gov - Batt > BLS451 failures?
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