Issues with Sabertooth 2x60 controller boards

I have 3 sabertooth 2x60 boards and all are causing different issues.

Hardware Setup

I have already followed official troubleshoot guide by dimension engineering but no luck.

Board-1:

Channel 1 of the controller board works fine, I have tested with pwm mode aswell simplified serial mode but channel 2 doent work with the same hardware setup as shown here sabertooth_diagnose.

Board-2:
This board shows status light green but no motor motions are observed with same setup as shown for board1.

Board-3:
This board doesn not drive motors and no status light is observed.

Contact Dimension Engineering support for further troubleshooting instructions:
https://help.dimensionengineering.com/ or,
support@dimensionengineering.com

Disconnect all wiring from the Sabertooth. Take each one that you have and set all the DIPs to the ON (up) position, except #4 set to OFF. Apply DC voltage of 7-30V. How do the LEDs behave on each? How does the fan behave on each?

@MYBOTSHOP_Support After disconnecting all the wiring and applying the 12V, I have observed the following behaviours on all three boards.

Board 1

  1. Status light turns on (green) and stays on.
  2. Fan spins for 2-3 seconds and then stops

sabertooth_startup

Board 2
Same behaviour as board 1

Board 3
Shows no response.

  1. No led lights
  2. No fan spinning