High Torque Servo Not Working But Micro Servo Does? (video included)

I recently got a Tactic TSX45 servo to replace my kit micro servo. Unfortunately Im getting all sorts of errors when I hook up my high torque servo but none when my micro servo is connected. There's no one single error so here's a few of them I get when I upload my program to the arduino:

  • avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified.
  • avrdude: stk500_recv(): programmer is not responding
  • avrdude: ser_send(): write error: sorry no info avail
  • avrdude: ser_recv(): read error: The device does not recognize the command.

Also, when I upload the program I keep getting a noise (Win10) that a device has been unplugged as well. Just for clarity's sake, I've recorded a video to show exactly how my setup looks, hopefully that helps.

Link to video

Appreciate any assistance with this!

UPDATE: Ok so I got it working, but Im still sort of scratching my head. When I plug the power cable into the 3.3V pin it all of a sudden powers the high torque servo. This is backwards to me because I figure the 5V pin would for sure power it but this doesn't seem to be the case. Any thoughts on that?

Hi !

Stop what you've been doing so far, and unplug your Arduino. Get on your knees and pray you didn't destroy anything yet.

Which power cable did you put in what 3.3 volt pin ? That sounds wrong and in that case it will be destructive, but hey, teach me something new i can do in the future.

Higher torque means more power. Power is displayed in Watts. Watts can be calculated from voltage and current (P = U * I) USB means 5 volts, and a typical USB port is limited to 500 mA.

Your trouble with uploading is caused by the device drawing too much current from the USB port. So the circuitry on your motherboard starts limiting the current. There's a few ways of doing that, but most of the times a fuse (which probably would reset upon removal of the too large load for a few seconds). No power means no device to be seen. So the errors and the "unplug sound" are normal phenomenons and to be expected.

NEVER ever do this again. ALWAYS power your servos from an external supply, which can at least deliver 1 A per servo. Even better would be to first find out what current your servo will pull and create a supply which can do more than that current.

As stated below: do connect all GNDs, or else you'll get into more trouble. There's no need to connect different 5 volt levels, don't do that either.

Oh interesting, yeah the tutorial I am going through has the micro servo hooked directly to the breadboard which is tied to the arduino's power output. I just thought the same logic applied to the slightly more powerful servo. Well looks like I will be picking up a battery pack holder to use as my external power supply in that case. Tutorials for servos are pretty vague with how to wire them, took me quite a few specific searches to find a guide on one. I appreciate your advice

One of the problems is that very very few servo specification pages / sheets actually mention the current requirement. And one must remember that every time a servo starts to move, it draws the so-called stall current, the maximum it can draw, even if only for a short spurt.