Servo Reversing Help

I hope someone can help me with this. I bought a Nirvana 2 this spring and really like the boat. The only thing I don’t like so far is the stock sail servo doesn’t have enough “grunt”.

I bought a Hitec HS645MG standard size servo with more pull and hooked it up. The issue I have is that the direction of travel is opposite of the standard servo for the same transmitter input, and the transmitter doesn’t have reversing switches on it.

One of my friends said that you could reverse the wires on the stick pot and that would reverse the servo. Does anyone have an opinion or solution?

Thanks in advance for your help.

I’ve done this - but it may be easier to do it in the Tx. Instructions for both are on the web.

Or: see if you can change the rigging or servo mount. Or…buy a complete cheapo radio - $40 at Tower.

Good luck.

Easy - Reverse the wires attached to the motor, inside the servo case. It should then work in reverse as you need. Easier than working inside the transmitter.

See: http://www.fatlion.com/sailplanes/servos.html

you also have to reverse the wires on the feed back pot.

“, you can reverse the normal direction of servo by swapping the wires that connect directly to the servo motor inside the servo case [b][u]as well as the little servo wiper that moves as the servo moves.”

john
[/u][/b]

Thanks for the feedback guys. I’m looking to modify the Tx instaed of cracking open te servo. Any sugjestions on that? Might even put in a reversing switch if I can find a place for it.

Thanks again.

If your going to try it out, the easiest method is to reverse the track connections on the pot in the transmitter. Far easier than doing it in the servo.

The pot will have 3 wires coming from it. leave the center one alone. It is connected to the wiper.
Remove the outside two, taking care to remember which went where. Swap them over and solder them back on.

Warning- try to use as little heat from the soldering iron as possible. excess heat can wreck the pot totally!! Been there before!!
You can use a crocodile clip as a heatsink to prevent damaging the pot track.

A lot easier than doing the same in a servo, AND swapping the motor connections as well eh??!

Thanks guys - i stand corrected :slight_smile: Good luck with the mods !

I had another Megatech sail servo in my Nirvana II fail on me again this weekend. Time for the Hitec to go in I think. I opened up the transmitter and swapped the wires on the pot and bingo, the servo was reversed.

Thanks to everyone who posted to my question. It all really helped me out.

Toby

Let me know how the Hitech servo works out. I assume you used the stock RX?

Don’t forget that servo city sells servos that have been modified for 180 dergree rotation, reverse rotation or continuous rotation. They charge a little extra for the mod but at least you know it will work.

Mitch

Yup. I haven’t had any problems with the RX or TX yet so I’ll keep using them until I do. That’s why I had to switch the pot wires. No servo reversing switches.

I’ll have her on the water this weekend to see what she does. At 6.0V the Hitec should have 133 in./oz. of torque. I heard from Megatech that their current sail servo only has 70 to 80 in./oz. of torque.

We’ll see.