Servos not working...now what?

[shaughn.treilly]

Hello all,
Was preparing for a flight tomorrow with my FT mustang, and while going through the control surfaces I discovered that both servos for the alierons arent working. I thought it might be just that channel on the receiver but when i plugged the elevator's servo into the first channel it worked fine. So then I plugged in the servo "y" lead into the second channel and it did not work (my elevator worked fine on this channel).
SO, it is either the servos or the extension leads, either way they are inside the wing.
Is my plane dead? Is there a way to melt the glue on the small spar/trailing edge? Or will that destroy it regardless?
Thanks team!

 

[Craftydan]

That depends . . . did you tack the servo wires down inside the wing, or are they free to slide?

If they're free to slide, you've got a better option:

- Remove the linkages
- turn the servo horns until they are clear of the top and bottom foam
- carefully cut the servos away from the wingtip
- tie a string to one servo horn
- gently pull the other servo/cable out of the wing, sliding the tethered servo and the Y into the wing.
- once the Y-connection is exposed, disconnect and pull the other servo out the other side using the tether.

Once you've gotten it out, it's a matter of testing the parts and fishing the replacements back in place.

If they're tacked down in one spot, you could cut a small hole in the wing where it's tacked, set it free and tape the plug you just cut out back into place. if they're glued everywhere . . . perhaps it's time to brush up on your building skills

 

[Corbarrad]

Your servos might be hooked up the wrong way around.
The middle pin on a servo is power, with the outer two being signal and ground respectively.
It's possible that you've twisted either the connector from y-cable to receiver or those on both servos by 180 degrees connecting power to signal and vice versa. This doesn't usually hurt the servo, but it will prevent it from working.
Take a look at the way the servo that's working is hooked up, then take a look at the lead for your y-cable and identify the terminals:
Brown or black is usually ground while red is power and orange or white is signal.
Make sure they're hooked up in the same direction and you have a chance that all your servos are working now.
There's usually markers for power (+), ground (-) and signal (squiggly line) on your rx as well

 

[shaughn.treilly]

I'm almost positive I did tack down the servos wires so I guess i will have to cut a whole. Im sure somthing just came unplugged but I never even thought about having to go in their. Do you guys put the servos on the outside for easier access or is this just a thing you have to deal with when using flitetest planes?

And thanks Corbarrad but the servos were working fine the flight before and I didnt unplug anything.

 

[shaughn.treilly]

Ok so I was able to fish out the extensions that connect from the servo to the "y" connector for both alierons. I tried them individually in my receiver and nothing for either one. So either both servos are dead or both came unconnected from their extensions or some combination of the two, either way the chances seem pretty high and now best case scenario I am able to cut into the wing exposing the connectors for the connects. Even if the extensions are the problem how would i fish them all the way through the wing and fuselage?

...Is my quicksilver dead?

 

[shaughn.treilly]

I fixed it!!!! The extensions came loose on both servos somehow. Regardless its all working, but I already ordered another mustang...oh well muahahah!

 

[PeterGregory]

Ahhh, connectors...

Connectors are the boon of all electronics.

While working on a military radio a bunch of years back, the design of the high-reliability bayonet mount connector had about 25 individually spring-loaded, gold-plated pins. The design took as much time as the advanced circuit boards we were designing. It also cost several hundred dollars.

 

[shaughn.treilly]

What are these connectors called or do you have a picture?