Servo mod - where did I go wrong?

Rcsailing.net Technology Discussions
1

I tried to modify a servo tonight to increase the travel, and seem to have failed miserably.

The servo I am modifying is a Hitec 645MG (sail up winch for my Victoria). The method for inserting resistors and increasing the travel of the winch is well documented (for example, in the US1M Construction Guide).

Anyway, I inserted the 2x220 Ohm 1/4 watt resistors as specified, did a nice little job with the soldering iron, and put the servo back together. Hooked it up to the Rx and Tx and tried it out. The result - 90 degrees rotation :-(. In theory I should have something close to 180 degrees rotation.

Before I pull it apart and try again - anybody got any ideas where I’ve gone wrong?

2

I ended up undoing and redoing the soldering and now have the desired degree of travel. I must have had a “dead” connection or something. The second attempt looks very messy, whereas I was rather proud of the first attempt. Oh, the irony!

3

Muzza what is the wattage of your iorn?

4

30 watt. At the upper end for use of a circuit board - but it shouldn’t be enough to cook anything (should it?)

5

30 Watts is a little much for servos wires, unless you’re really careful with a lite touch. I have a 15 Watt iron for small stuff.

Another thing that you need to be aware of is the potential for short-circuits or grounding connections (like where you soldered the resistors) inside. Be careful when stuffing the wires back in.

6

Thanks for that. I do have a 15 watt iron somewhere - but it seems to have gone astray during our move, and I couldn’t find it when I looked. Anyway, all seems to be well now.