625 mg glitches  
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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> Radio Manufacturer Direct Support >> Hitec/MultiPlex Radios- Ask Hitec Customer Service >> 625 mg glitches
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625 mg glitches - 1/25/2004 11:43:39 PM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Hello,

I just finished and built a great planes patty wagstaff extra. I had 625 mg's on all the surfaces except the rudder. I'm using a digital on the rudder with a pull/pull setup. Three of the four servos that I bought brand new from servocity are glitching. When you operate them slow they work normal. WHen you use full deflection quickly, they jitter a bit. What should I do? I replaced the two aileron servos with some new 645's I had but I still have a jittery elevator servo.

any help appreciated.

craig
       Post #: 1

RE: 625 mg glitches - 1/26/2004 2:45:26 AM   
modeltronics


 

Posts: 224
Joined: 2/26/2002
From: Horizon City (near El Paso), TX, USA
Status: offline 		Just an idea. If you plug the servos into a receiver on the bench one at a time do they glitch with the fast movement? If they don't do it on the bench one at a time but do it in the plane when everything is all together you could have a voltage drop someplace. When you make a servo move a surface fast there is a large current draw that will cause a voltage drop anywhere you have any resistance. Long leads of too small of a gage will cause enough voltage drop to cause all sorts of problems.

Pete

(in reply to psk560)
       Post #: 2

RE: 625 mg glitches - 1/26/2004 3:13:03 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		I'm using a I4c servo isolator with a 6.0volt 2700 mah NIMH battery for the servo power. Both servos going to the elvator have the same heavy duty gauge servo extension. Only one servo makes this noise. One aileron used to glitch also but I replaced the aileron servos with some nib 645's. I'm using the same extension and it's working fine. I wonder if its the fact that they are high speed servos thats making them do this. I connected the old aileron servos to a reciever on the bench after reading your post and they are still jittering.

craig

(in reply to modeltronics)
       Post #: 3

RE: 625 mg glitches - 1/27/2004 3:16:40 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Did some more testing. THese servos work fine when used with a ppm reciever. I've already sent the original 9cap and 9 channel pcm reciever to futaba for checking. Cost me 50 bucks to get them tuned and ceramic filters changed. Why are these servos only jittering with the pcm reciever? Hitec please help.

craig

(in reply to psk560)
       Post #: 4

RE: 625 mg glitches - 1/27/2004 5:33:40 PM   
MikeMayberry



Posts: 2800
Joined: 1/15/2002
From: Poway, CA, USA
Status: offline 		Long ago the HS-605's (older brother of the 625) had an issue with Futaba PCM receiver due to the timing. We had corrected that problem well over 5 years ago and I have not heard of any similar issues since then. It sounds like a power issue. Try running another batter directly into the receiver.

Mike.

(in reply to psk560)
       Post #: 5

RE: 625 mg glitches - 1/27/2004 10:47:53 PM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		MIke,

Thanks for the reply. I changed the servos to the 645 high torque ones and they do Jitter also but not at the endpoint. Isn't that strange?

craig

< Message edited by psk560 -- 1/31/2004 4:00:38 AM >

(in reply to MikeMayberry)
       Post #: 6

RE: 625 mg glitches - 1/28/2004 5:31:43 PM   
MikeMayberry



Posts: 2800
Joined: 1/15/2002
From: Poway, CA, USA
Status: offline 		Interesting... The 625 and 645 are identical servos; the only difference is the gear ratio.

Mike.

(in reply to psk560)
       Post #: 7

RE: 625 mg glitches - 1/29/2004 2:29:49 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Ok Mike, MORE TESTING DONE


1. Disconnected the switch and ran straight batteries (6.0V) to the i4c and pcm reciever: still glitches
2. Got rid of the i4c and went 6v to reciever w/o switch: still glitches
3. Ran 6 volt straight to a ppm reciever: DID NOT GLITCH?
4. Ran i4c at 6V and pcm reciever with no servo extension: still glitches
5. Ran i4c at 4.8V and pcm reciever with extensions: glitches a little/not as much as 6 vol

This thing is driving me crazy. It only glitches on one side of the travel at about max throw. It wiggles a bit and then stops. Not all of the servos are doing this now. The two 625mg ailerons did glitch but they are now 645mg's and they are working gitter free. The two elevators are still 625mg's and only one of them glitches. No y harness and they are both the same heavy gauge wire and the exact same length. The radio and pcm reciever just came back from futaba for servicing and they are up to spec. Why won't these 625's work right with a pcm reciever? ARGHHHH!!!!!


NEXT TEST: Replacing both of the 625mg's in the tail with two more 645mg's. Will let you know how this works out.

Craig

< Message edited by psk560 -- 1/29/2004 2:30:29 AM >

(in reply to MikeMayberry)
       Post #: 8

RE: 625 mg glitches - 1/29/2004 3:15:46 AM   
jkeze



Posts: 141
Joined: 1/6/2002
From: Canton, MI, USA
Status: offline 		I also have a new 625 that is doing the same thing. Even sent it back and Hitec said no problem found. It would only oscillate on one side of travel and if you moved the stick to the extreme end of travel quicky. Even though the 645 is identical to the 625, but only the gear is different, this could be the problem. It seems to me that maybe the faster transit time along with my running it on 6.0 volts makes it so fast that the electronics in it overshoots and causes it to hunt to find its position. I am only using it on a nose gear steering so I am not to concerned but would never use it on a control surface because of this.

(in reply to psk560)
       Post #: 9

RE: 625 mg glitches - 1/29/2004 4:20:15 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Thank you Jkeze,

for a week now I've felt like I was crazy!


Craig

(in reply to jkeze)
       Post #: 10

RE: 625 mg glitches - 1/30/2004 3:07:17 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		MOre testing:

Unfortunately, the 645mg's are not perfect either. I"ve had them jitter a bit around center. I'm absolutely fed up with this garbage. I've changed about everything. No servo seems to work. I've spent over 400 bucks outfitting three big planes with these hitecs and I've tried almost every one on my extra and it still doesn't work.


Questions for Mike:

1. Does it matter if the servos are universal or futaba with the futaba recievers?
2. Would mixing a futaba 645 and a universal 645 make a difference?


I sent you an email mike. Please respond.

craig

< Message edited by psk560 -- 1/31/2004 4:01:27 AM >

(in reply to psk560)
       Post #: 11

RE: 625 mg glitches - 1/30/2004 7:16:17 PM   
MikeMayberry



Posts: 2800
Joined: 1/15/2002
From: Poway, CA, USA
Status: offline 		No, those factors will not matter.

(in reply to psk560)
       Post #: 12

RE: 625 mg glitches - 1/31/2004 3:58:38 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Mike,

I noticed you mentioned that there was a timing issue with the old servos and futaba's pcm recievers. They recently (in the last couple of years) changed thier pcm recievers and transmitters again. (1024) Thier new pcm recievers do not work with their old ones and vice versa. Maybe the servo timing needs to be addressed again. I would gladly lend you my new pcm futaba reciever to check it out.

craig

(in reply to MikeMayberry)
       Post #: 13

RE: 625 mg glitches - 2/7/2004 11:26:30 PM   
shess65-RCU



Posts: 74
Joined: 12/28/2001
From: Morristown, TN, USA
Status: offline 		This is amazing. I was sent this thread by a friend who know I was having the same problem. I have Hitec 605mg servos that I was moving from my H9 Cap 232 to the Patty Wagstaff Extra 300. The servos never had a glitch in the Cap.

I just bought a Futaba 9C radio with the PCM receiver so I decided to use it on this expensive setup. After hooking all the electronics up, I found that my elevators would jitter like crazy at one end of the range if I move them fast. I also note they will jitter at center if I release them quickly from deflection. They do this a bit and quit. I switched to a normal PPM receiver and they quit.

Steve

< Message edited by shess65-RCU -- 2/8/2004 1:31:19 AM >

(in reply to psk560)
       Post #: 14

RE: 625 mg glitches - 2/8/2004 1:17:21 AM   
psk560



Posts: 609
Joined: 3/7/2002
From: Appling, GA,
Status: offline 		Shess65,

Thank you for confirming that it's not just me. I'm using a futaba 9cap also. Mike is going to test these servos with a newer futaba reciever and let me know if they can reproduce the problems. Its not the plane at fault here, it seems to be a timing issue with the pcm reciever and the servos. I'll keep you posted.

Craig

(in reply to shess65-RCU)
       Post #: 15

RE: 625 mg glitches - 2/8/2004 1:30:51 AM   
shess65-RCU



Posts: 74
Joined: 12/28/2001
From: Morristown, TN, USA
Status: offline 		Thanks for the update. I would appreciate any resolution you get, if you would let me know.

(in reply to psk560)