Issue with Maestro 6 and voltage regulator

My setup: A Maestro 6 driving 6 Power HD-1800A servos. Servo power is coming from a 5v 2A wall-wart being run through a S18V20F5 5V voltage regulator. When I connect the power to the Maestro 6, several servos start moving independently and can’t be moved through the Maestro Control Center. If I use a 6v battery pack, the Maestro and servos work just fine.

The voltage regulator is providing almost perfect 5v. Is the Maestro sensitive to being that close to the low end? Should I try a 6v or 9v regulator?

I’m stumped. Could it be a ground loop of some kind? Both the wall-wart and the computer driving the USB are plugged into the same house circuit.


The Maestro’s minimum operating voltage is 5V, as you mentioned. I suspect your servos are drawing enough current or causing enough noise to fluctuate the input voltage enough to affect the Maestro. It is generally good practice to use a slightly higher voltage than the minimum required to give you a buffer. Wall-warts sometimes output an actual voltage that is slightly higher than what they are rated for (since the voltage will drop a bit when under load), so you might try removing the regulator and powering the Maestro directly from the wall-wart. If that does not work, I think your suggestion of using a 6V regulator or wall-wart is a good idea (9V is probably a bit too high for the servos). Another option is to power the Maestro separately from the servos (e.g. using the 5V supply for your servos and a 9V regulator for the Maestro’s logic power).

By the way, I am not sure what your intentions were by using a 5V regulator between the 5V wall-wart and the Maestro, but this is generally not necessary for devices like motors and servos.


Thanks. I’ll give the 6V regulator a shot. I stuck the up/down regulator in there because the power here isn’t always reliable. The Maestro itself is picking up power from the USB

Well, that was a bust. The 6V regulator shows 5.55V when not connected but drops to 1.95V when I plug it into the Maestro 6. That drop happens with only 1 servo plugged in. My 6V battery pack maintains that voltage with all 6 servos online. Sadly, analog electronics are not my strong suit.

What 6V regulator did you use and what was your power source? It sounds like the regulator you chose might not be able to handle enough current.


S18V20F6 It’s rated at 2A. It’s being powered from a 2A wall-wart. The idle current for the HD-1800A @6V is 5mA. I get the voltage drop plugging just one servo in.

It sounds like you are using the same 2A wall-wart you mentioned in your original post, which is 5V. If this is the case, I would expect that regulator to handle around 1.5A (from the efficiency graphs on its product page). I suspect there might be some problem in your setup. Could you post some pictures of your setup that show all of your connections?