HD-1235MG overheating and fails

I have four HD-1235MG servos being used to move a 3ft frame around. Sometimes they pull as much as 14 A total for all four servos, but it works fine either from a 7.4V LiPo or a 7.4 V power supply that can deliver the current. The problem I have is that although the servos are not enclosed and the arms are not binding the loaded servos get really hot and eventually start acting poorly then fail, probably from being too hot. I have a bag of dead servos from this problem.

I am going to mount temperature probes on them with relay shutoffs and have the code monitor temperature and basically put it in a low torque state to cool off if they get too hot. But I wondered the following:

  1. Am I doing something wrong? I use the same setup to control 4 much larger 12V traxis servos doing a lot more work (a 6 ft high bigger version of the same system) and nothing goes wrong with the servos like this, they go and go.

  2. Is there a specification I am missing like on the HD-1235MG servos that would explain them getting hot when they actually do work.

  3. Are the HD-1235MG servos not really designed to deliver torque for very long. Pretty sure I am not even reaching max torque on any one servo based on the current draw.


From just your description, it sounds like those servos are under powered for your application, but it is hard to say for sure. Can you post more information about your setup? Are all four servos mounted to the same rigid structure (e.g. is there a chance they are “fighting” each other)? Are the servos drawing 14A constantly when they are just holding position or is that when they are moving? How long do they run before failing? Can you post some pictures of your setup that show how everything is connected?


I have 2 servos rated at 600 oz-in and they cost me around 150 each (hiTec). I hate to even suggest this but it may be the quality of the servo.
I would test the start up and heavy load AMP draw. You can even use a infrared thermometer to check temps.
But also as Brandon suggested it they may be slightly out of whack (my technical term) and causing them to fight each other.

But I could be way off base, I just never used “Power” brand servos before.