Quick Blue Box Question + - side of the motor.

Model Railroader General Discussion (Model Railroader)
1

Getting ready to add Led’s to a old Blue Box Athearn but it has been hard wired. I think the bottom of the motor is the - side and top +, am I right?

Cuda Ken

2

I think you’re right because the bottom of the motor used to touch the frame, which was the left-hand (negative) rail when running from DC block control.

3

Check the power trucks. The motor should ground on the frame at the bottom and the top connection should be to the metal arm that extends up and over the power truck and the power trucks’ bolster (that the frame rest on) should be the same polarity as the right rail

4

“Check the power trucks. The motor should ground on the frame at the bottom and the top connection should be to the metal arm that extends up and over the power truck and the power trucks’ bolster (that the frame rest on) should be the same polarity as the right rail”

Thanks that helps.

5

Apply your best deductive reasoning… and then clip an LED and resistor in with alligator clips and try it before the final wiring :slight_smile:

Jim

6

I’ve been using and fixing Athearns for 26 years. The bottom of the motor is - and the top is +.

7

[#ditto]

8

Uh, hate to tell you guys but the polarity reverses when you change directions. Moral of the story is to add a diode in the string so the current can only flow one way. You also get directional lighting that way