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Old Mar 12, 2012, 03:47 PM
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it does it with the esc too, so i don't think its the servos
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Old Mar 12, 2012, 08:04 PM
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any ideas? its still having the same issues with isolated power to the servos (only signal to osd)
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Old Mar 12, 2012, 09:48 PM
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Starting from the logger, how long are the wires going to the ESC? where along them are the taps going to the BEC and sepic reg.?

-Hugo
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Old Mar 12, 2012, 09:52 PM
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its around 6 inches (15cm) , the wires are tapped in around 3-4cm from the logger
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Old Mar 12, 2012, 11:32 PM
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As per this diagram, you do not have any power or ground tying the receiver to the osd.

did you have your servo power and ground running through the osd originally, and separate it during troubleshooting,

or has it always been set up this way...

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Old Mar 12, 2012, 11:35 PM
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Eagle tree OSD uses that power from the receiver. It does not use the power from the VTX.

The power and ground terminals on the VTx pass straight through as a courtesy, but are not connected anywhere in the OSD.

so you should run your receiver power and ground to the osd.

and it is your choice to run the video power and ground through the osd, or bypass it.

either way it is the same.

I can see from your diagram that there is no ground loop, but rather a lack of a ground, and a lack of a power supply.

That may be your problem.
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Old Mar 12, 2012, 11:44 PM
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From the Eagle Tree OSD manual
"Normally, the OSD Pro system is powered via the flight battery, which connects to the “Batt” connection of the eLogger V4. If the battery you are
connecting to the eLogger V4 is greater than 4S (about 16V), the throttle monitoring Y cable included with the Logger V4 needs to be connected
between the “Throttle” input of the eLogger V4 and any receiver channel (or a 5V to 6V BEC), to provide backup power to the eLogger V4. Note: the
voltage supplied to the throttle Y cable cannot be greater than 6V! "

Sounds like eLogger has a linear regulator so if you use a very high voltage pack its regulator
may not be able to supply enough current. None of that is really relevant to his problem
however. His first diagram had Rx power coming through the OSD to power
the servos, and later one bypasses the OSD while still powering the servos. Either way,
the OSD already has the power it needs.

ian
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Old Mar 12, 2012, 11:46 PM
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so the video system is fine, but the ground voltage in the servo circuit? is causing the problem? seems pretty confusing............
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Old Mar 12, 2012, 11:50 PM
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I have no idea what the problem is. But I'm pretty sure that needing to power the OSD
from the Rx (which you've already tried) is not the problem. I still think you should try
some different servos. Shouldn't be hard to just plug in some random ones you've got around.

But yes, generally crosstalk noise (that isn't at Rf frequencies) has something to do with
grounding, or lack thereof.

ian
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Old Mar 13, 2012, 12:07 AM
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I'm with Ian on this, I have no Idea what is causing it, but we all agree on the fact that you have an issue that must be resolved.

I'd try different servos also.

Here are a couple of other thoughts.

I would definately run power and ground from receiver to servos. and pass them through the OSD.

also, Maybe it is your filter

Here is a DIY on LC filters. they are very simple to build and work well...

wrap your wires through the ferrite rings as many times as you can...

http://www.rcgroups.com/forums/showp...7&postcount=14
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Old Mar 13, 2012, 12:11 AM
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Keep in mind that if he runs power and ground from Rx through the OSD to servos he is purposely creating a ground
loop, since power and ground are also coming from the eLogger. As he had it last wired, he was running
power and ground directly to servos, and only the signal wire through OSD, which should avoid the ground loop
and avoid any power system noise from the servos, getting into the OSD. Except it didn't work any
better than when Rx power/ground was going to OSD.

Perhaps the noise is coming from the eLogger itself (which is directly connected to battery
and ESC, pre-filtering). Wouldn't really explain why the servos introduce the noise though, since
the Rx is powered from a separate BEC.

ian
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Old Mar 13, 2012, 12:20 AM
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Quote:
Originally Posted by Daemon View Post
Keep in mind that if he runs power and ground from Rx through the OSD to servos he is purposely creating a ground
loop, since power and ground are also coming from the eLogger. As he had it last wired, he was running
power and ground directly to servos, and only the signal wire through OSD, which should avoid the ground loop
and avoid any power system noise from the servos, getting into the OSD. Except it didn't work any
better than when Rx power/ground was going to OSD.

Perhaps the noise is coming from the eLogger itself (which is directly connected to battery
and ESC, pre-filtering). Wouldn't really explain why the servos introduce the noise though, since
the Rx is powered from a separate BEC.

ian
would it be the UBEC then? perhaps something is causing the ubec to give out noise when current is pulled? ill try different servos and a Ni-MH battery for RX separately, ill report back tomorrow

Taiping
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Old Mar 13, 2012, 12:23 AM
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Maybe the UBEC. If you're using the Turnigy UBEC from HK, it is known to be very low noise, and has pretty good filtering.

The problem is, if you use a separate battery, it has to share the ground somewhere, to pass a valid signal
through the OSD. As I said earlier, any time the OSD is connected to your Rx and servos, you
have potential complications.

ian
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Old Mar 13, 2012, 12:26 AM
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right.... ill try the servos tomorrow but i highly doubt it because if it was only the servos, it wouldn't do it when i apply throttle....
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Old Mar 13, 2012, 12:55 AM
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Corvallis, OR
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Quote:
Originally Posted by Taiping View Post
any ideas? i kept the video signal to th osd and unplugged everything else and its fine, the text will only move when the servos/esc has a signal
Just start with the absolute basic 1 battery setup and then add components
one by one until the problem reappears. So start with a 1 battery setup with
just a cam, VTx, and Rx and see if the problem persists. Then add OSD. Then
add current sensor. Ect. Make it as basic as possible and then add things in a
piecewise manner. When the problem reappears you know which component is
causing the problem and will have a better time figuring out what is wired
wrong, rather than trying to solve a single problem within the entire system as
a whole.

-Blues
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