My controller shuts the burner off after 1 to 1-1/2 minutes. Indications are the flame sensor circuit is causing the problem, since the sensor line shows a positive voltage
When the burner turns off, and the LED indicates ""AC POWER REVERSED". When the
Unit is cold, the line reads zero volts.
I'm capable of making the repair myself; I need a schematic of this unit. Where can I
Get one?

Ron Ingraham

Sorry Ron but this is the only service/trouble shoot guide that I have for now. The board you are working on has some major problems and is obsolete. In most cases the drawings and info has been removed since it is obsolete and not considered repairable by the manufacturer. This is a replacement only part according to W/R.

Pay special attention to page 1

http://www.white-rodgers.com/wrdhom/pdfs/06_Cat_pages/Cat_06_pg0259_264.pdf