Everything WAS working OK.
Futaba FP-T8UP tx + EZUHF. Channel 7 on Rx controls camera Pan (just removed Tilt servo).
Ch 7 is set to be controlled by the CH7 'pot' on the tx.
Problem:I switch on Tx + UHF, then when I switch on the plane, the camera servo immediately slams round to full lock (to the left). The 'pot' on the tx does nothing.
1) I have disconnected the pan servo from the rx and connected to a servo tester - all working ok.
2) Due to previous experiments trying to setup a Head Tracker (unsatisfactorily), I have checked in the tx menu that 'Trainer' is INH with Ch 7 & 8 'off'.
I'm sure the problem is something 'silly', but I'm damned if I can think of the solution.
Any suggestions, please.
UPDATE:
I thought I had solved this problem, but now discovered what the problem is:-
Using Immersion Vtx, have recently upgraded from a 5v camera to a 12v one. Am using a 12v step up regulator between the vtx & the camera.
Thing is - IF I leave the vtx to camera wire DISCONNECTED - the camera pan servo on Ch 7 (or Ch 8) works perfectly.
BUT - as soon as I connect the vtx to camera wire the Pan servo immediately goes to full lock and will not answer to radio tx control.
I have the vtx to cam wire taped together with the pan servo wire - I wonder if now that the camera voltage has been stepped up to 12v (from 5v) this is causing interference to the servo wire ??
Added this to 'bump' thread up from bottom of list
Noisy step-up-reg sounds prime suspect to me!
Try easiest things first!
Obvious first step is to separate the two wires
and/or add a Ferrite ring on pan servo lead (try near servo end first, then near rx end)
and/or try a low pass filter on the reg output supply.
One or a combination should work...
Bigmouse - thks for your input - think I have solved it myself.
The new 12v camera has a 5 pin wiring socket on the rear. The 5 to 12v step up regulator wiring has a 3 pin plug on the end. At the time of purchase I asked how to fit 3 into 5 and was told to fit the 3 to the LEFT end of the socket - which I did and all worked OK.
Last night I removed the camera to work on something else and think that when I replaced the cam I fitted it upside down so the left end of the 5 pin socket became the right end - if you see what I mean ! Have now moved the 3 pin plug and all OK !!
Well I thought I had this sorted - but I haven't.
Starting from the vtx, which is supplied by full 11.1v 3s, 5v is output to EZOSD - the 5v 'passes' through the osd and then goes through a 12v step up to the camera.
I have now found:-
IF the power supply to the vtx is DISCONNECTED - plugging the osd to cam wire in STILL causes the pan servo on ch7 to lock on full left lock.
I am wondering if I have some sort of earth loop problem, but cannot understand why it is only the pan servo that has a problem and all the other servos are OK ?
This got me thinking and I have just tried another servo - Hey Presto - all problems seem to have gone !
I still am baffled as to why a servo works perfectly when plugged into a servo tester, yet goes berserk when a camera wire is plugged in with no elec supply.
Oh well, it's currently thundering down with rain and this problem is keeping me occupied !!
Oh I have this before, took me an age to find out what it was.
Do a quick test for me, unscrew the pan servo arm srew that locks the arm to the servo. Does it not work fine ?
The put the screw back in, but unplug the camera at the camera end. Does it work fine again now ?
Coyote
Thanks for an, as ever, very interesting reply. How on earth did you ever discover that?
Anyway, in my case, the problem was the pan servo itself - one of those small, nasty, cheap, Chinese plastic geared ones. I have changed the servo for another (same type, hadn't got anything else) and all is fine again. Will try the servo again, when I have calmed down, with the servo horn screw removed.
I assume you are suggesting that the horn screw can go in too far and short the servo internal pcb ??
Its the camera`s inside, the circuits touches the cameras case, the case is screwed to the bracket, the metal bracket is screwed with a metal screw to the servo and that makes the link electrically from the camera to the inside of the servo.
I descovered it when it would work fine off the bracket or with the camera cables not connected. I wondered if it was rf related, but even in close proximity, as long as there was a break ( electrically ) from camera to servo screw it was fine
What I did was drill the hole that the servo screw goes through on the bracket so it does not touch the metal, problem solved, it stopped altogether :)
You could also try a shorter screw but then you loose strength
Yes Coyote everything you say did apply to me - If I disconnected the camera wire all was ok, but even with no power to either the vtx or the osd, connecting the camera caused the problem to occur - this is why in one of the above posts I wondered if I had some sort of earth loop. Yet I couldn't understand why the problem suddenly happened when all I had done was take things apart and put them back together again !
In a way I'm glad this has happened, as, if it had happened whilst in the air, for me it would have been a major problem trying to pilot a plane whilst looking 90 degs to the left ! (Accepting my vision isn't great whilst flying LOS)