Hitec servo jitters 7954sh & 7955TG
08-16-2016, 08:28 PM
#1
Hitec servo jitters 7954sh & 7955TG
I will post videos
But before I do here's the issue:
When using my older 3 PM for Futaba radio I got no jitters, or glitching or excessive movement while at idle. Actually no noise at all!
Purchased a new Futabs 4PLS and using any of those hitec servos they're moving more than the than they should at rest.
-- tried high-voltage 7.4 and I tried regulated 6 volts and 5 volts. Use different batteries to use different wires even tried a new Futaba receiver , and they're still glitching . I'm back on the old FAAST 3channel radio and no glitching or movement at all.
Only thing I did not do is try a different 4PLS radio. I did use other brand servos including Futabs BLS and other digital high-voltage Futaba servos and also savox hi-volt servo. None of those servos made any noise or movement at idle. The only thing that fixed the movement at idle, was to widen the dead band on the hitec servos. The monster size hitec servos do not have deadband adjustment with my hvp10 servo programmer( perhaps the newer one does?)
Here are some pictures of what I've been using
But before I do here's the issue:
When using my older 3 PM for Futaba radio I got no jitters, or glitching or excessive movement while at idle. Actually no noise at all!
Purchased a new Futabs 4PLS and using any of those hitec servos they're moving more than the than they should at rest.
-- tried high-voltage 7.4 and I tried regulated 6 volts and 5 volts. Use different batteries to use different wires even tried a new Futaba receiver , and they're still glitching . I'm back on the old FAAST 3channel radio and no glitching or movement at all.
Only thing I did not do is try a different 4PLS radio. I did use other brand servos including Futabs BLS and other digital high-voltage Futaba servos and also savox hi-volt servo. None of those servos made any noise or movement at idle. The only thing that fixed the movement at idle, was to widen the dead band on the hitec servos. The monster size hitec servos do not have deadband adjustment with my hvp10 servo programmer( perhaps the newer one does?)
Here are some pictures of what I've been using
Last edited by Hermit 713; 08-16-2016 at 08:56 PM.
08-16-2016, 08:42 PM
#2
Well for some reason I can't add all the photos to check into it just probably do it from my computer other than on my cell phone I'll do a video and show you what I experienced with the servos and the Futaba radios.
Has anybody else experienced or had a similar experience to mine ?
Has anybody else experienced or had a similar experience to mine ?
08-16-2016, 08:48 PM
#3
I realize there have been problems with jitters on these servos especially when using on airplanes . Issue I had heard of mainly was using the longer connections or longer servo lines but this is not the case with rc cars. I also realize that the hitec servos in general (the ones that I mentioned ) in particular, have some issues with their boards I don't want to get in that there's been plenty of discussion On the FG forum about it.
My question really is is this an issue with all the new Futaba equipment like the THFSS RECIEVERS( new radios and receivers) (again, the older FAAST system worked w/o glitches)or is this just a real oddball experience ????
Thank you.
My question really is is this an issue with all the new Futaba equipment like the THFSS RECIEVERS( new radios and receivers) (again, the older FAAST system worked w/o glitches)or is this just a real oddball experience ????
Thank you.
08-16-2016, 09:17 PM
#4
I came across this today and it confirms what I believed to be... The pulse is somehow digested differently by the hitec servo. Or perhaps the servos are indeed showing there insuficiencies with updated transmitter/receivers. In other words, it confirms that the hs79XX servos have a bad board setup that self induces vomit.
"Servos are positioned by issuing a positive pulse from the receiver to the servo whose width determines the servo arm/wheel position. Typically, a pulse width of 1.5 milliseconds (that's 1 1/2 thousandth of a second) will center the servo, a pulse width of 0.8 milliseconds will rotate the servo to one extreme and a pulse of 2.2 milliseconds will rotate the servo to the other extreme. The resolution or granularity of servo movement can be dependent on the make and type of servo. Servos also have a characteristic called "dead band" which is the amount the width of the pulse may change before the servo will actually try to move to the new position. t is desirable to have a certain amount of dead band or else the servo will always be attempting to align itself with very minute changes in the pulse width which can result in buzzing, chattering, and higher than normal current consumption"
"Servos are positioned by issuing a positive pulse from the receiver to the servo whose width determines the servo arm/wheel position. Typically, a pulse width of 1.5 milliseconds (that's 1 1/2 thousandth of a second) will center the servo, a pulse width of 0.8 milliseconds will rotate the servo to one extreme and a pulse of 2.2 milliseconds will rotate the servo to the other extreme. The resolution or granularity of servo movement can be dependent on the make and type of servo. Servos also have a characteristic called "dead band" which is the amount the width of the pulse may change before the servo will actually try to move to the new position. t is desirable to have a certain amount of dead band or else the servo will always be attempting to align itself with very minute changes in the pulse width which can result in buzzing, chattering, and higher than normal current consumption"
08-17-2016, 08:01 AM
#5
I will post videos
But before I do here's the issue:
When using my older 3 PM for Futaba radio I got no jitters, or glitching or excessive movement while at idle. Actually no noise at all!
Purchased a new Futabs 4PLS and using any of those hitec servos they're moving more than the than they should at rest.
-- tried high-voltage 7.4 and I tried regulated 6 volts and 5 volts. Use different batteries to use different wires even tried a new Futaba receiver , and they're still glitching . I'm back on the old FAAST 3channel radio and no glitching or movement at all.
Only thing I did not do is try a different 4PLS radio. I did use other brand servos including Futabs BLS and other digital high-voltage Futaba servos and also savox hi-volt servo. None of those servos made any noise or movement at idle. The only thing that fixed the movement at idle, was to widen the dead band on the hitec servos. The monster size hitec servos do not have deadband adjustment with my hvp10 servo programmer( perhaps the newer one does?)
Here are some pictures of what I've been using
But before I do here's the issue:
When using my older 3 PM for Futaba radio I got no jitters, or glitching or excessive movement while at idle. Actually no noise at all!
Purchased a new Futabs 4PLS and using any of those hitec servos they're moving more than the than they should at rest.
-- tried high-voltage 7.4 and I tried regulated 6 volts and 5 volts. Use different batteries to use different wires even tried a new Futaba receiver , and they're still glitching . I'm back on the old FAAST 3channel radio and no glitching or movement at all.
Only thing I did not do is try a different 4PLS radio. I did use other brand servos including Futabs BLS and other digital high-voltage Futaba servos and also savox hi-volt servo. None of those servos made any noise or movement at idle. The only thing that fixed the movement at idle, was to widen the dead band on the hitec servos. The monster size hitec servos do not have deadband adjustment with my hvp10 servo programmer( perhaps the newer one does?)
Here are some pictures of what I've been using
08-17-2016, 09:05 AM
#6
The servos are actually moving although slight. This is occurring w/o any servo horn on!. The Futaba servos make no noise while sitting. Video to follow😀...
08-23-2016, 06:02 AM
#7
08-23-2016, 09:01 AM
#8
Try running the servos in T-FHSS(Norm) mode or S-FHSS(Norm) modes depending on the receiver that you have, and see if this changes anything. Also, make sure that your receiver is rated for the 2 cell lipo. Futaba's manual specifically states to only run their digital servos in T-FHSS(High) and S-FHSS(High) modes, and to run the right voltage for the receivers.
08-30-2016, 10:39 AM
#9
didn't make any difference .
Try running the servos in T-FHSS(Norm) mode or S-FHSS(Norm) modes depending on the receiver that you have, and see if this changes anything. Also, make sure that your receiver is rated for the 2 cell lipo. Futaba's manual specifically states to only run their digital servos in T-FHSS(High) and S-FHSS(High) modes, and to run the right voltage for the receivers.
I put the receiver up to A Hitec servo programmer to see what the pulse was doing and while using the 4PLS and the T. Reciver from Futaba the last digit was bouncing around 1524-1529....the last number would go up/ down so fast it was indistinguishable. when I Hooked up old transmitter / reciver, it was solid. There wasn't any chance in last number while watching the pulse.
I will try my 18mz transmitter and see if it acts the same way ( numbers changing quickly) and see what I can find .
Last edited by Hermit 713; 08-30-2016 at 10:57 AM.
08-30-2016, 11:01 AM
#10
Futaba radio 18 MZ
OK I checked with the 18 MZ and NO movement at all it was 1546-steady not like the other four channel 4PLS with the R304SB (that is the newest receiver TFHSS ) the Futaba makes. Again the 18 MZ does not use the T-type receivers though. If I owned the WC edition 18 channel transmitter, I could compare directly .
Off the radio goes to be checked out by Hobbico
Off the radio goes to be checked out by Hobbico
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