Advice to wall power Micro Maestro with Hitec HS-7980TH


I need a bit of newbie handholding as I try to properly power with a wall power adapter my simple setup using a preassembled Micro Maestro for a single Hitec HS-7980TH (7.4 V) Servo.

Max torque is key for my application so I’ll need to utilize the 7.4V capability of this one servo.

I’m considering using Item #'s : #1464, 9VDC, 3A Wall Power adapter - #2449, DC Barrel Jack to 2-Pin - #2180 JST RCY Plug, Female

Is this sufficient for my setup?

Thanks in advance!


From information I found on ServoCity’s product page for that servo, it looks like the current draw could be as much as 6A at stall when running at 7.4V. So you will probably need a power supply that can handle that much current. Additionally, you might consider using a power supply with a voltage that is within the voltage range of the servo (4.8-7.4V). Then you would not need to use an additional regulator to drop the voltage down from 9V like you would with the power supply you referenced.

The rest of your components should work together.


Thanks for your input, Derrill…

I just found this…

This says that @ 7.4V, my stall current is 9 Amps! :smiley:

Am I SOL in finding the right wall power supply that can do this?

Are there any rules of thumb where I can choose some power supply that’s close to the specs it shows? 6V operating / 7.3A stall current or 7.4V operating / 9A stall current? If I can get close enough, that’ll do for now just to get started.

Thanks again!

An update… I am looking into this…

I wanted to avoid the battery route because I didn’t want to be forced into a situation that would cause me to recharge (and possibly completely discharge) the battery for such a simple task. My project is not a model airplane or RC rockcrawler. I need to rotate a ~15lb LED monitor 90 degrees and back again on command. The (overkill) high torque is for overcoming inertia. This would be eventually enclosed after mock-up and testing and charging a battery, in this instance, would be a pain in the patushka!

If there’s a way to use a wall power adapter for this application, I am open to any suggestions!


A little more searching…

Does this have a snowball’s chance in hades to make this servo work?

Its the best I could find within the parameters… 7V / 7.85A


It looks like the battery pack you linked to has a maximum discharge rate of 9A, so that would probably work. The AC adapter might work if you are careful to not stall the servo. Please note that with servos that draw as much current as those do, you should power the servo separately from the Maestro board. However, be sure you still connect a ground from the servo power supply to the Maestro.


Hello, Dave.

You might be interested in this project by another customer involving a monitor that can rotate 90 degrees:

The parts list is here: … c=121570.0


Thanks again, Derrill.

I will try the AC adapter first since that’s my ultimate goal…

I’ll keep you posted if all goes well or naught!

Merry Christmas…

Thanks for the find, David… I will definitely do my reading up!