Tony Hwang wrote, on Tue, 23 Dec 2014 14:04:50 -0700:

If you indeed need board, it could be universal type with wiring adapter
harnesses and instruction sheet. Board is quite pricy,
I hope you don't need one.

I was only able to get two quotes for the board, the first
being $450 and the second being $250, neither of which was
in stock.

I spent at least an hour (or more) on my back, looking the
board over, and I don't see a single burn mark or obviously
bad component:
https://c1.staticflickr.com/9/8669/1...03e811cb_b.jpg

I did figure out the terminal sequence though, which you can see
I drew a simplified diagram of on the chassis in the picture above.
COM === the unswitched neutral out of the 24VAC (nominal) transformer
RED === the power to the thermostat (which is switched in the thermostat)
WHI === the power coming out of the thermostat to call for heating
YEL === the power coming out of the thermostat to call for cooling
GRE === the power coming out of the thermostat to call for the fan

The transformer, nominally 24VAC, tested at 28VAC, by the way.