AV 130 issue

D

Dominic

Member
Hi
Slight problem with the AV130 tonight. Noticed that the U shaped large gear that's around the the av130 for roll was slightly bent in one place and thus the potentiometer was missing when it got near to one of the ends.

We have bent it back but the roll was then stopping quite a way short of where it should be on that side (we assumed it was doing this because of it missing that bit before it had spun to what it thought was the limit).
We then (rightly or wrongly) tried to correct the potentiometer by turning the adjuster screw on it but now the servo goes straight over full lock to one side. Is there a way to sort this or have we screwed the potentiometer and if so how expensive are they to replace?

We have tried plugging the servo directly into a receiver to eliminate the DJI from the equation but its still doing the same thing no matter what position the stick is in.

Any help would be much appreciated!
 

R

RTRyder

Merlin of Multirotors
A couple things you need to do, first make sure the connection between the pot and servo is solid, the roll arch will go full travel to one side if the inline connector isn't fully seated and making good contact. Second, you need to make certain the arch gear is flat and will be in contact with both the pot gear and servo gear across the entire range of travel. If it's bent and the tracking is off you have two options, diassemble the arch and carefully straighten the gear by lightly squeezing it in a soft jaw vise, or replace it with a new one.

Once the arch gear problem is fixed, loosen the bottom set of roller supports so the arch gear can be moved away from the pot gear and servo gear. With either a servo tester or using a port on an RX, connect to the roll servo and set the tester or TX control to the middle position, now turn the roll pot until the servo stops spinning, this is the center position. Remove power from the servo and carefully lower the arch back down so the arch gear is now in contact with both the servo and pot gears making sure the platform is as level as possible while doing so. It's very easy to make contact with the pot gear before the servo and throw it off center, so take your time and try to get both to mesh at the same time. If you think you missed getting both at once just power up the servo again and find center with the arch not making contact with the gears and try again. Once you have it meshed and centered, tighten up the lower rollers so the arch moves freely in its travel but tight enough so there is no vertical travel of the arch between the top and bottom rollers. Power up the servo again and make sure the platform is centered or very close to it. Don't worry if it's off a little bit, you can compensate by using the centering adjustment in the gimbal setup screen.

Let me know if you have any problems getting it setup, it's not all that bad after you've done it once or twice. The main thing is make sure the connector between the pot and servo is solid, it's easy for it to slip apart slightly and look like it's connected but not making contact inside, check it first and then do the centering.

Ken
 

A

andrewrob

Member
Hi Ken, thanks for the quick reply.

I've tried the above but cannot get the servo to neutral. There is no change in speed at all across the whole stick or with moving the potentiometer at centre stick.
The only thing I can get it do is change direction if I reverse the plug to the pot. Is there an internal adjuster on these servos?

Thanks
 

R

RTRyder

Merlin of Multirotors
andrewrob said:
Hi Ken, thanks for the quick reply.

I've tried the above but cannot get the servo to neutral. There is no change in speed at all across the whole stick or with moving the potentiometer at centre stick.
The only thing I can get it do is change direction if I reverse the plug to the pot. Is there an internal adjuster on these servos?

Thanks
Click to expand...

There is no adjustment other than the position of the pot. It's a 10 turn pot so you may have to give it quite a few turns before the servos stops and it's a very narrow band where it does stop. If you go by it you'll see the servo start turning in the other direction so that's something to watch for. I'd start by turning the pot all the way to one end of its travel and then go back about 3 turns before you power up the servo then keep going slowly in the same direction with the pot until the servo slows then stops. Ultimately I think there's only about 1 or 2 turns of the pot either side of center that's actually used by the mount, so if you're out near the limit it will take a lot of movement to get it back to where it needs to be.

I use a HiTec servo tester when I'm working on my 130s, but it should work exactly the same with a TX and RX, all you need is the 1500us signal that tells the servo it's at neutral point and center stick on the elev channel will do it just as well as a servo tester.

Ken
 

A

andrewrob

Member
Still can't get anywhere with it.
I've got it on the elevator channel now with everything zeroed. I'm turning the potentiometer very slowly from end to end and the servo never stops or changes direction just keeps going at full speed.
Any ideas?
Thanks
 

R

RTRyder

Merlin of Multirotors
andrewrob said:
Still can't get anywhere with it.
I've got it on the elevator channel now with everything zeroed. I'm turning the potentiometer very slowly from end to end and the servo never stops or changes direction just keeps going at full speed.
Any ideas?
Thanks
Click to expand...

Has to be a problem with either the pot or the wire and/or connections between it and the servo, only possible thing it could be if nothing else works.

Ken
 

A

andrewrob

Member
RTRyder said:
Has to be a problem with either the pot or the wire and/or connections between it and the servo, only possible thing it could be if nothing else works.

Ken
Click to expand...

It must be the pot then as when I plug the pot lead in the other way it just reverses the servo so there must be a connection.

Do any of these look right? Thanks again

[URL="http://uk.rs-online.com/web/p/trimmers-potentiometer-rheostat/4867150/"]http://uk.rs-online.com/web/p/trimmers-potentiometer-rheostat/4867150/

http://uk.rs-online.com/web/p/trimmers-potentiometer-rheostat/4601988/

http://uk.rs-online.com/web/p/trimmers-potentiometer-rheostat/4601900/




[/URL]
 

Bartman

Bartman

Welcome to MultiRotorForums.com!!
dominic,
did you change the positions of any of the wires going from the servo to the pot? reversing the two outer wires (of three total) of the pot will make it tell the servo to do the opposite of what you want it to do. in other words, as the servo moves out of position the pot will tell it to go further out of position when the two outer wires are reversed.
i don't have an av-130 so i can't give you specific advise on that mount as Ken can.
bart
 

A

andrewrob

Member
Bartman said:
dominic,
did you change the positions of any of the wires going from the servo to the pot? reversing the two outer wires (of three total) of the pot will make it tell the servo to do the opposite of what you want it to do. in other words, as the servo moves out of position the pot will tell it to go further out of position when the two outer wires are reversed.
i don't have an av-130 so i can't give you specific advise on that mount as Ken can.
bart
Click to expand...

Hi Bart
No none of the wires have been reversed, but when I reverse the plug the servo continuously spins in the opposite direction. At no point with any input from the TX or position of the potentiometer can I make it stop.
 

A

andrewrob

Member
Ignore everything above, I've just put a meter across the potentiometer and its working fine. I guess its the servo then? I'll try swapping it with the tilt one tomorrow and see what happens when I'm more awake! Thanks for all of your help!
 

Bartman

Bartman

Welcome to MultiRotorForums.com!!
good luck with that. if you're absolutely certain that the wires at the pot are correct then maybe one of the pot wires came off inside the servo... i kinda doubt the servo would just stop responding without a failure somewhere on its circuit board.
can you post a pic? i'm curious to see which plug you're referring to.
thanks,
bart
 

A

andrewrob

Member
Hi all
I realised earlier that I tested black and red on the potentiometer but not black and yellow. Looks like the yellow side isn't working so I need a new potentiometer. I've also tried hooking the other Savox servo up and that's doing the same thing.

I've also tested right back to the circuit board in the servo and all connections are fine.

Is there anything special about these pots or will any 10 turn 5k one do?
 

Bartman

Bartman

Welcome to MultiRotorForums.com!!
i'm sure the most devoted potentiometer afficionado would suggest there's a difference but I don't think there is as the pots in the servos themselves are about as junky as they come.
glad you found the problem.
bart
 

A

andrewrob

Member
Thanks Bart. I'll have a look and see what I can come up with and thanks to Ken for all of the tips. At least I know how to adjust it properly now, just a shame I've learnt the hard way before coming to find out what to do!
 

A

andrewrob

Member
The new pot is working ok but a little slow, I looked on photohigher's site and its down as having a 10 turn pot but I think its actually more like a 3 that was on ours before. With the 10 on that I have now its far too slow, considering changing to a 1 turn but don't know if that will be pushing it or not!

We've also done away with the 360 gimbal add on as we haven't really got the money for a piclox and video is pretty poor from it without so have gone back to the standard fixed legs and stabilising the gimbal through the DJI and its a made a major improvement to video.
So if anyone is after a nearly new 360 gimbal at a very good discount drop me a PM!
 

A

andrewrob

Member
Another problem!
I replaced the potentiometer with a 10 Turn 5k one. It worked fine but was quite lazy, as the one the AV130 came with was somewhere around 3-4 turn.
I managed to pickup a 1 turn yesterday so thought I would try it to see if it worked. Any slight movement and the gimbal would lock over as far is it would go.

So, I assumed that the potentiometer had too few turns so put the 10 turn back in. I am now getting the same problem with the 10 turn!

When I turn the pot the servo (with the gear off so it doesn't turn the roll axis) it acts as it should do. When I have the gear on it locks straight over. Adjusting settings in the DJI doesn't seem to make any difference either.

Can someone check the wiring colour on their roll pot and tell me what they are? Wondering if I've wired it up wrong.

I've got black in the middle with yellow next to it then red on the pin that's on its own

Thanks! (again)
 



You must log in or register to reply here.
Top