HiTec Servo Lock Ups


Hey ROVers,

Just finished my 2 year adventure getting a OpenROV Version 2.4 built.

I was too far into the design when I found out about the servo being under powered for the design.

I could not go for the chassis re-design (which was quite elegant) so I opted for the “let’s throw more power at the problem approach”. I replaced the original v2.4 servo HS-81 with a HS5085-MG and also replaced the plastic horn with an aluminum one. I then sanded down the chassis everywhere that was providing resistance with the tube and made extra sure that the alignment on the servo horn was such that the electronics sort of “floats” in the tube. The wire harness provides most of the resistance but the power of the HS5085-MG easily overcomes that…or so I thought.

The design has worked great in test dives except I have locked up the servo - twice. I replaced it thinking that I had burnt it up but the second one locked up yesterday in a test (after 3 successful test dives) and I know I checked to make sure that the chassis was floating when I sealed the tube.

My question is…are the servos dead?

I have read about buying a HiTec programmer to reset to factory defaults and I disassembled one of the servos to verify that the servo gears were physically jammed by something.

I will gladly spend the $60 for the programmer if I know that it will restore my servos.

Any help would be greatly appreciated.