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Hitec 5955 problems - 1/5/2005 2:22:29 AM   
cwoodstx


 

Posts: 73
Joined: 1/9/2002
From: Plano, TX, USA
Status: offline 		I received 4 Hitec 5955 servos last week and for the last 2 days have been trying to get them setup on a 28% Edge rudder using pull-pull. I have been using Hitec servos with the programmer for 2 years now on many different planes, so I don't think my problems are user error - at least not in this case. I have so far tried 2 of the 4 servos.

The problems I have encountered are:
1) the servo exhibits a pulsed jitter at the end points, I had to reduce the end points to where the servo arm (as measured from the spine) had less than 50 degrees of throw before the pulsed jitter stopped. In contrast my 5945 servos will go 70+ degrees with no issues.
2) in addition to the pulsed jitter at the end points the servo will jitter in the midrange at random locations. I even tried voltages below 6V and the jitter remains.
3) The second servo I tried, in addition to the above problems, would lock in the full throw position for 1-2 seconds, then return to center. This was even after I reduced the end points to produce only 45 degrees of rotation on the servo arm. Once this problem started it was easy to reproduce.

Additional information:
1) Before I noticed the version 1.04 sticker on the first servo, I had reset servo #1 with the programmer before I started setting center and end points. On the 2nd servo I did not do a reset, I just set the center and end points - thinking the 1.03 software on the programmer was incompatible with the 5955. This did not make any difference.
2) I tried different DB settings between 1 and 5 – no difference.
3) I tried loosening and tightening the pull-pull wires – no difference.
4) Finally I substituted a Hitec 5945 to make sure it was not a problem in my overall setup, and it worked perfectly.

These results are very disappointing. If its something I'm doing wrong I would very much appreciate some help. If Hitec would like for me to send them in for an evaluation, I'm happy to do that. In the mean time I won't be putting any 5955's in my planes.
       Post #: 1

RE: Hitec 5955 problems - 1/5/2005 1:33:31 PM   
gjdeluca


 

Posts: 25
Joined: 9/18/2002
From: Mechanicsburg, PA, USA
Status: offline 		Unfortunately, I too am very disappointed with the HS-5955 "super servo" from hitec. I purchased 10 of them. I experienced the following problems with them.

1. The center did not maintain its programmed center position. I programmed the center and the end points. Then I used the manual servo test function of the programmer to test the center and end points. The center was different from where I programmed it by 2 to 3 degrees. I repeated the procedure 6 times on 2 servos and got the same results each time. Oh yeah, I did reset the servo each time before I programmed it.

2. I applied a slight amount of pressure to the servo arm to simulate the weight of a control suirface. The servo began to jitter just like the JR 8411.

I too have been using the 5945 servos for 3 years. I have programmed them many times, so I also know I wasn't doing anything wrong.

This is very disappointing to say the least. I waited many months to get these servos because I won't buy any of the other brands of digitals - they all have something that I don't like about them. These new hitecs were suppose to be the anwser to all of our problems in big gas planes. But it looks like we are sadly disappointed again.

Supposedly these servos were field tested for many months and when released were suppose to be right. Wonder what happened with that. Wonder who the field testers were and why these problems weren't identified and corrected.

I also wonder if hitec intends to address these issues, and if so, how long it will take.

(in reply to cwoodstx)
       Post #: 2

RE: Hitec 5955 problems - 1/5/2005 3:06:41 PM   
mglavin



Posts: 5200
Joined: 11/29/2001
From: Elverta, CA, USA
Status: offline 		This is the first I have heard of any problems with regard to these servos. I'll look into your concerns later today (Hitec Service isn't open yet) In the mean time I have some of these servo I have yet to play with and will do so now.

I believe these NEW servos were coded to limit rotation somewhat unlike the earlier digital servos, I'll check.

Did your servos work satisfactorily out of the box without reprogramming?

_____________________________

Michael Glavin
RCU Community Moderator
Hitec * Multiplex Field Representative

(in reply to gjdeluca)
       Post #: 3

RE: Hitec 5955 problems - 1/5/2005 3:19:14 PM   
gjdeluca


 

Posts: 25
Joined: 9/18/2002
From: Mechanicsburg, PA, USA
Status: offline 		If I remember correctly, I didn't experience any jittering problems right out of the box. I didn't check to see if the servo returned to the same center position, so I can't comment on that.

My biggest concern was encountered during programming where the center position was 2 to 3 degrees different than where I set it to be and the jittering at center when I applied a small amount of pressure to the servo arm.

I already returned my servos to the vendor where I purchased them, so I can't try anything with them. But if you want to talk with me on the phone while you are testing yours, I would be more than happy to do that. My phone number is (717) 766-3144.

(in reply to mglavin)
       Post #: 4

RE: Hitec 5955 problems - 1/5/2005 3:57:52 PM   
cwoodstx


 

Posts: 73
Joined: 1/9/2002
From: Plano, TX, USA
Status: offline 		Michael: I programmed both of my servos before using them, so I don't know if the problem was pre-existing. For servo #1 I did a RESET, on #2 I did not. Is it possible that the 1.03 software on my programmer is the problem? If so how can I upgrade to 1.04?

I sent in both servos to Hitec but I have access to 2 more that have not been programmed, so I can try any suggestions you might pass along.

Thanks for looking into this, I am a Hitec fan and would really like to use these servos.


(in reply to gjdeluca)
       Post #: 5

RE: Hitec 5955 problems - 1/5/2005 4:03:33 PM   
cwoodstx


 

Posts: 73
Joined: 1/9/2002
From: Plano, TX, USA
Status: offline 		Michael: one more followup - before I sent them in I measured the amount of resistance it took to cause jitter. I found that around 80 ozs was the point at which the servo would jitter, and this seemed to be independent of its rotational position, i.e. did not matter if it was at full deflection, half deflection, etc.

Hope that helps.

(in reply to cwoodstx)
       Post #: 6

RE: Hitec 5955 problems - 1/5/2005 4:13:30 PM   
Crash90



Posts: 2310
Joined: 10/5/2002
From: Cressona, PA, USA
Status: offline
just following this thread.

(in reply to cwoodstx)
       Post #: 7

RE: Hitec 5955 problems - 1/5/2005 5:46:41 PM   
mglavin



Posts: 5200
Joined: 11/29/2001
From: Elverta, CA, USA
Status: offline 		Guys

Out of the box the servos seem to work fine. They centered @ 1500us and rotated to the programmed end point without issue.

I then RESET one, programmed center and 90* end-point. All seemed well. Activated MANUAL servo test function, center requires nearly a 30us offset (1530us). The offset seemed consistent at extreme travel, movement was decreased and increased in either direction. Also noted the AUTO servo test function was functioning with limited movement, looked like MAX travel I could swing was 30us. I did not note any jitter issues, please expand on what your experiencing in this regard.

Two programmers and three servos the results seem consistent.

At this point there seems to be an issue with the programmer and revision V1.04.

We've queered Hitec's Engineer's on the problems mentioned above and have previously asked for information on the V1.04 revision. Your patience while discovering said problems is greatly appreciated. Information will follow in this regard as ASAP.

< Message edited by mglavin -- 1/21/2005 4:09:10 PM >

_____________________________

Michael Glavin
RCU Community Moderator
Hitec * Multiplex Field Representative

(in reply to Crash90)
       Post #: 8

RE: Hitec 5955 problems - 1/5/2005 6:15:41 PM   
famousdave


 

Posts: 2263
Joined: 9/16/2003
From: Bradenton , FL, USA
Status: offline 		The question I have to ask is why in God's earth would you be using one (two???) of these TG servos on a 28% plane rudder??
The programmer would not be needed if you were setting up one, so are you really trying to set up two on rudder...?

I have used a single 5945 or 8411 with no issues ever.. and I fly very hard 3D. One 5955 seems like complete overkill to me.. two is just plain wasteful..

I have one installed on a 35% I am building... didn't need to break out the programmer...

Hopefully I am missing something here...

DP

(in reply to mglavin)
       Post #: 9

RE: Hitec 5955 problems - 1/5/2005 6:48:41 PM   
cwoodstx


 

Posts: 73
Joined: 1/9/2002
From: Plano, TX, USA
Status: offline 		desertpig: your comments are not helpful to this thread, but I will respond anyway. I did NOT say I was using 2 servos on the rudder, only that I had tried 2 different servos. Secondly, even with one servo I find it beneficial to program the center so that the arm is perpendicular to the servo at center without having to use sub-trim in the TX. Setting end points is also very helpful because if you set the end points to max availabe rudder travel, and use 150 ATV on your TX, you will get maximum resolution.

Michael: The jitter appears only after load is applied, just exercising the servo with the programmer is not sufficient. Try holding the servo with your hand at various points of rotation, or use something like a fish scale so you can see the load in lbs/ozs as you apply it. I found about 5lbs (80 ozs) was the starting point for jitter. Thanks again for the quick response, I am happy to help work through this issue and come to a resolution for everyone's benefit.


(in reply to famousdave)
       Post #: 10

RE: Hitec 5955 problems - 1/5/2005 6:50:27 PM   
woodscra


 

Posts: 895
Joined: 12/10/2001
From: frisco, TX, USA
Status: offline 		Michael:

Have you put any kind of force on the servos? Please hook them up to an elevator, aileron, or even better, a rudder pull-pull setup and test again. This is where jitters occur. This is the testing that needs to be done.

When did you receive your servos? Ours came just last week from Tower.

_____________________________

Craig

(in reply to famousdave)
       Post #: 11

RE: Hitec 5955 problems - 1/5/2005 7:56:17 PM   
gjdeluca


 

Posts: 25
Joined: 9/18/2002
From: Mechanicsburg, PA, USA
Status: offline 		The jitter I experienced occurred after programming and while still on the programmer in the manual servo test mode. I just applied a very small amount of pressure to the servo arm and the servo tried to push the servo arm back to center in a jittery manner, much like you see happening with the JR 8411 servos. I wish I would have tried this before I programmed the servo when I had it connected to my receiver.

If you have a servo there that has not been programmed, maybe you could try it. Just apply a very small amount of pressure to the servo arm while the servo is connected to your receiver and at idle. It only takes a small amount of pressure, like would occur on an elevator at neutral without the engine running.

(in reply to woodscra)
       Post #: 12

RE: Hitec 5955 problems - 1/5/2005 8:38:25 PM   
mglavin



Posts: 5200
Joined: 11/29/2001
From: Elverta, CA, USA
Status: offline 		I'll try and setup something up with a model on a surface before I leave later today for Southern California and the IMS AMA Show. Things are hectic today and my time is limited. Thus far I've only used the programmer. I'll try some additional tests with a servo in a model as soon as possible.

I received my servos from the same batch as everyone else.



_____________________________

Michael Glavin
RCU Community Moderator
Hitec * Multiplex Field Representative

(in reply to gjdeluca)
       Post #: 13

RE: Hitec 5955 problems - 1/5/2005 8:45:17 PM   
famousdave


 

Posts: 2263
Joined: 9/16/2003
From: Bradenton , FL, USA
Status: offline
quote:

ORIGINAL: cwoodstx

desertpig: your comments are not helpful to this thread, but I will respond anyway. I did NOT say I was using 2 servos on the rudder, only that I had tried 2 different servos. Secondly, even with one servo I find it beneficial to program the center so that the arm is perpendicular to the servo at center without having to use sub-trim in the TX. Setting end points is also very helpful because if you set the end points to max availabe rudder travel, and use 150 ATV on your TX, you will get maximum resolution.

Michael: The jitter appears only after load is applied, just exercising the servo with the programmer is not sufficient. Try holding the servo with your hand at various points of rotation, or use something like a fish scale so you can see the load in lbs/ozs as you apply it. I found about 5lbs (80 ozs) was the starting point for jitter. Thanks again for the quick response, I am happy to help work through this issue and come to a resolution for everyone's benefit.




Sorry I wasn't trying to be a jerk! I just think a servo of that strength is not needed, but that is your choice, not mine. For all I know you are getting them for free!

I see what you are saying about lining up the arms without sub trim, but I have never had problems getting the arms to line up perpendicular for a pull pull setup either single or tandem / tertiary. On direct drive arms like the 3" MLP or Airwild uni-hubs with nelson bellcrank arms I get very close to 0 degrees every time. What kind of arms are you using that you need to realign to center ? I do remember that the plastic hitec or DuBro arms did not line up, but hopefully you are not using those...

DP

< Message edited by desertpig -- 1/5/2005 8:46:11 PM >

(in reply to cwoodstx)
       Post #: 14

RE: Hitec 5955 problems - 1/5/2005 9:09:21 PM   
XJet


 

Posts: 3215
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline
quote:

ORIGINAL: gjdeluca
The jitter I experienced occurred after programming and while still on the programmer in the manual servo test mode. I just applied a very small amount of pressure to the servo arm and the servo tried to push the servo arm back to center in a jittery manner, much like you see happening with the JR 8411 servos. I wish I would have tried this before I programmed the servo when I had it connected to my receiver.

Could it be that the small battery in the programmer is incapable of providing enough current to feed these hi-torque servos when you place a load on them?

Have you tried connecting them to a decent flight pack and checking again?


_____________________________

When I'm not here, I'm at RCModelReviews

(in reply to gjdeluca)
       Post #: 15

RE: Hitec 5955 problems - 1/5/2005 9:27:19 PM   
cwoodstx


 

Posts: 73
Joined: 1/9/2002
From: Plano, TX, USA
Status: offline 		Xjet: yes I have. Actually I first noticed the problem after I had installed the servo in the plane and hooked up the pull-pull and was checking things out with the TX. The RX battery pack was a freshly charged 6V pack. In addition these servos are supposed to operate on 4.8V as well, which is what the programmer supplies.

Nice thought though, thanks for the input.

(in reply to XJet)