You have sw r1.4, the symptoms correlate to a missing dc supply to the cell. Do you hear the relay "click" shortly after moving the switch from off to auto?
If it does, measure the dc voltage between pins 1 and 2 as shown in the link from post #2 "Troubleshooting the Main Board"
If the current is missing, inspect the Thermistor and K1 or K2 solder and the connector.
You can replace the Varistor later should you decide to keep the PCB.
I do not know how to diagnose component problems on a low voltage system. I do own a rudimentary voltmeter. I have ordered the thermoster and varister kit. I will pull the main when it powers down and inspect for other damage. I noticed a hairline fracture in thermoster as well. Will post more pics. Thank you all for chiming in!I would have to agree that unless that varistor shorted and took out a fuse somewhere that the unit should fully power up without it.
I fear that the surge that took the MOV (Metal Oxide Varistor) could have taken something else upstream out. But at least you know it's the DC power supply section so I would still say it's repairable. Do you know how to diagnose component problems on low voltage electronics?
If not, I would cut out the damaged MOV and see if that helps. If not, consider a new board, unfortunately.
Edit:
It appears the thermistors control DC current. That is worth looking into as well. You might want to order all three parts and do what we call a "shotgun" repair and see if then works. Good luck