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Do you have the manual? Did you check the other possible causes in the manual?
Are there any visual defects on the board, like a burn or discoloration? Does the burner ignite then go out or not light at all? If it doesn't light do you hear a buzzing/ticking sound when it should fire up? An visible leaks from the heat exchanger? did you check for broken wires/bad connections?
Could be a bad flame sensor rod. The next step would be to replace it. It's unlikely but if the burner is clogged near the flame sensor that could be causing this.
If the burner hasn't been cleaned/checked in a while you should do that first
Ok, if you're sure about the connections then you're down to the sensor or the board.
Typically 4 to 12 micro amps. Note that's micro amps not milli amps
It is measurable but you need a meter that can read micro amps.
Given the extremely low voltage signal from the sensor the connections must be flawless. the behavior you describe, in light of past errors, still indicates a flame rectification issue. Since you don't have any errors showing now it does cast more doubt on the board. But if you don't have a meter that can read micro amps I'd replace the flame sensor rod primarily because it's a lot cheaper than a new board.
I'm in NH, I don't know any suppliers North of the border.