Lennox 19w94, 17w82, EGC1 board repair high voltage ignition weak.

[neisg1]

19w94, 17w82, EGC1 board repair high voltage ignition weak.
A couple of months ago I had trouble with my furnace failing to light the high voltage was weak. Replacement of the control circuit board corrected the problem. In our cold climate I lucky had a spare on hand the weather has been very cold this winter.  So now I no longer have a spare if this happens again. So I set about repairing the original board. After several hours of tracing circuits and testing parts I came to the conclusion that the high voltage capacitor that drives the ignition coil was bad. It tested good but failed under load.  This Capacitor is a 2.2uf 250v that runs around 170v it feeds the ignition coil through an SCR that is pulse triggered. Basically it's a capacitive discharge ignition system. I replaced the capacitor with a 2.2uf 650v unit (much larger safety margin) at a cost a couple of dollars. The board is now fully functional without having to buy a new one at retail prices of $250-$400.

[walker]

congratulations.