I didn't know which section to put this in as the problem covers several aspects so....
For months my Victoria yacht has been fine, electrical wise, servos/radio/batteries. I am using a High Torque metal geared sail arm servo with a cheapish Acoms servo for the rudder. My radio was a GC Radioline 2.4ghz one, a cheapo but works fine.
Suddenly 2 weeks ago, I sent the yacht out into the lake after checking everything and it went out about 50 yards then decided to go round and round in circles with no response from the radio. We eventually got it back and found that the sail servo was twitching and the rudder servo had gone past it's maximum throw, and had tried to do a complete circle I reckon, bending the rudder push rod into a banana shape. There was no response from the radio, so we turned everything off and I manually twisted the servo arms back into the normal position.
Tested it out again on dry land and everything worked normally, back in the wet stuff and exactly the same thing happened......I gave up that day. On getting home I decided to change the Acoms rudder servo for a high torque servo identical to the sail arm one. On testing, everything worked fine, until hitting the water again the next time out, exactly the same problem....I then came to the conclusion it was the cheap radio at fault, so changed the Tx and Rx for another 2.4ghz system that I KNEW worked in my other models, a Planet 5. Everything tested fine on the kitchen table, until the Victoria race yesterday.
Pre-race check was fine, I managed about 20 yards out and the whole thing locked up again, resulting in the ever-decreasing circles scenario...
Up on my bench, I again manually turned the servos back to their normal position and dry tested the set-up. Fine for a few seconds, both servo's responded then suddenly twitched, did their own thing without any input from me, and the rudder servo started making a banana again from the rudder push-rod.
Surely it couldn't be 2 different radios at fault? So having an Esky 2.4ghz Tx with me, which I used for my fast electrics, I whipped the Esky Rx from the FE and changed it in the Victoria. Turned it on and exactly the same thing happened! Servo's went into a dancing routine, then locked up. This basically proved that it wasn't the radio to blame, a fellow club member even took the receiver out of his own Vicky and tested it in mine with the same thing happening, a lock up.
Right, so now 4 completely different transmitter/receivers have been in the boat and the problem continued. Everything was suggested from low batteries, bad wiring, bad on/off switch etc, but by eliminating these one by one, the problem remained.
This morning on the kitchen table, I tested it yet again, within seconds the servos locked up, so I whipped them out of the boat and connected them up minus servo arms, they work faultlessly......no matter what I do to try to get them to malfunction, they wont.
Do you think it possible that it's the load on the servos that is sending them loopy? I am fast running out of ideas and have started thinking about where I put my lump hammer.....
