Here's another video showing troubleshooting a problem with a Jazz board fridge where the evap fan motor was not running. I troubleshot this problem all from the Jazz board (minimal disassembly) without having to tear down the freezer compartment to access the evap fan motor. 

On 6/23/2021 at 10:04 AM, jroedl said:

You're reading line voltage from the motor and N from the board input. 

The board functions as a switch for the evap fan. It switches Neutral to the fan motor. What's the voltage across an open switch? This test proves that the switch on the board for the evap fan motor was stuck open. It also proved that 1) the board was getting a valid Neutral and 2) the motor was getting valid Line voltage. The problem is that the motor was not getting Neutral, which is supposed to be supplied by the board. A 120 VAC load needs BOTH Line and Neutral-- a valid power supply, or a complete circuit-- to do its work. It can get Line voltage all day lone but without a return path to then power supply (ie., Neutral), then no electrons will move in the circuit. No electron movement = 0 amps = 0 watts = no power = no work. 

On 6/23/2021 at 10:04 AM, jroedl said:

So if you put your meter probes in the same  spot with a working board what would you get for a reading?

What's the voltage drop across a closed switch? If the board was doing its job correctly -- switching Neutral to the load (evap fan)-- then I would have read 0 VAC across those points on the board because the switch on the board would have been closed. 

This is all basic electricity and basic circuits stuff. Nothing high tech or tricky going on here. These are the basic, building block skills that every tech needs to be able to troubleshoot any kind of electric circuit, from simple (like this one) to complex. We teach all this in the Core Appliance Repair Training Course at Master Samurai Tech.

On 6/25/2021 at 9:50 AM, jroedl said:

I understand how electricity works. I was just looking for help to understand.

This is an inherently contradictory statement. You either understand basic electricity or you don’t. No need to feel defensive or inadequate. 

On 6/25/2021 at 9:50 AM, jroedl said:

If you're teaching , then maybe throw your meter back on those test points to show what a proper functioning board would look like.

I already explained that to you both in my reply and  in the video. If you’re learning, then watch the video again and follow along. I even sketch on the schematic to show how the board functions.

On 6/25/2021 at 9:50 AM, jroedl said:

Thank you for your help.

Glad to help anytime. Thanks for your questions!