How to repair the furnace control board.

The IFC or control board is considered to be unrepairable. Problems related to the flame safety control are NOT repairable. UNSAFE OPERATION could result. However, there are parts of the board related to several mechanical relays that can have simple repairs done.
This repair is called the "halo" repair. Where you find heavy traces on the back of the board used by the relays, when there is a bad connection, the solder joint will melt and the result is the connection is broken from the solder moving away from the joint. These connections can be resoldered for a more or less permanent repair. When this repair is done, and the unit put back in service, all safety operations should be checked.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.