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I'm trying to give this old ESC a new purpose, but I can't find any info on the polarity of the motor wires.


The insulation shield was pulled up on both wires, making them touch together.


Seller said it worked, but I'm not doing a thing until it's safe.

I have a MC-112B also, and found the manual here on RC10talk, but no polarity mentioned about the motor wires.
https://www.rc10talk.com/viewtopic.php?f=82&p=391494#p391494







I know these have reverse, but the potentiometers made me think there was already a bias dialed in for the correct motor polarity.

Is brown supposed to be negative with these vintage Futaba ESC's, or is it blue?

Yellow is positive and blue is negative. I don't think reverse was proportional I want to say it was like 30% power with no variable, the pot adjusts where the brake stops and the reverse starts. Not like most where you have brake for a few seconds then reverse or brake on the first pump and reverse on the second

Much thanks for that! Exactly what I needed to know. Would not have guessed that was yellow and not brown or earth.

Now I can get back to this project with peace of mind. Thanks again!

On my Playtron Doberman I mounted a 112b.
My motor wires are orange and blue.
I have the orange as positive and the blue as negative.
It's hard to see but the upper connection on the motor is labeled +

Edit: Hard to beat GoMach to the punch
Chuck

That does look more like orange than brown.


Thanks for confirmation!

Just noticed I put the wrong end on for the power connector - try again

GreenBar0n wrote: ↑Sat Jul 27, 2024 3:08 pm Much thanks for that! Exactly what I needed to know. Would not have guessed that was yellow and not brown or earth.

Now I can get back to this project with peace of mind. Thanks again!

I was thinking of the Tamiya motor wires which are yellow and green, the esc is more of an orange I guess.

GoMachV wrote: ↑Sat Jul 27, 2024 3:15 pm

GreenBar0n wrote: ↑Sat Jul 27, 2024 3:08 pm Much thanks for that! Exactly what I needed to know. Would not have guessed that was yellow and not brown or earth.

Now I can get back to this project with peace of mind. Thanks again!

I was thinking of the Tamiya motor wires which are yellow and green, the esc is more of an orange I guess.

Looked a dirt tinted yellow or brown to me

GreenBar0n wrote: ↑Sat Jul 27, 2024 3:14 pm Just noticed I put the wrong end on for the power connector - try again

Unless you have a vintage Kyosho. They were opposite of Tamiya.

As soon as I plug this in, LED is red, and full throttle is on, no response to Tx.

Turn all pots down to 0, no throttle. No response from Tx.

Turning Neutral pot from 0 to 1 is full throttle again. No response from Tx.

This thing is busted right?

Usually when they blow it's nothing or wot all the time. Follow the instructions step by step on setting the pots and you might be just fine.

Also, It almost looks like the esc is plugged into the battery slot? Channel one is steering and two is throttle ....

GoMachV wrote: ↑Sat Jul 27, 2024 6:06 pm Usually when they blow it's nothing or wot all the time. Follow the instructions step by step on setting the pots and you might be just fine.

I've tried every setting on the pots, it should react to the Tx. My 112B has no problems like this one, pretty sure the 111B is blown, and probably from the PO letting those motor wires touch. Check out the burn mark on the original molex connector (ebay sellers pic):

GoMachV wrote: ↑Sat Jul 27, 2024 6:08 pm Also, It almost looks like the esc is plugged into the battery slot?

I put Spektrum DSM guts in that old Futaba Rx.


EDIT: The ESC was plugged in to the Batt connector, but unfortunately it does the same thing when plugged in to any of the connectors.

Thanks!

Think I'll start the return process on this 111B, the auction said it was tested, but not thoroughly enough.

@GoMachV called it, ESC in batt port, and pots out of whack.


Red LED on high-point and reverse for the pot adjustments.

Thanks again!

Oh awesome