A 20 minute start cap replacement turned into a 2 month series of learning experiences. I’ll understand if you choose to stop reading here, but there is a moral to the story.
Mistake #1 was to make an assumption and replace the wrong cap.
Mistake #2 was to ignore mistake number 1 and assume that the fan motor was somehow at fault.
I should have already mentioned that the problem wasn’t with the compressor, but with the fan motor up top. Last year the fan would start if I barely touched it, but that no longer worked this summer when I decided to fix it so I looked for other causes.
Mistake #3 was to go deeper and deeper into the machine. I research as I went, but I was always one step behind.
I’ll shorten the story here and mention that I removed the motor in the heat of the sun and it only took about 6 hours.
Ok, so the motor worked.
So I ordered the correct cap and replaced them both and attempted to put everything back together.
Late in the afternoon, when I was almost finished after working for hours after I should have stopped for the day, I attempted to make the final 6-pin connection the the control box.
Everything worked, except that hi and low fan were backwards.
So instead of waiting until I could think the next day I swapped position of the red and blue wires and plugged the connector back in (apparently upside down).
There was a rather loud bang when I hit the switch and not even the furnace worked after that.
And now some useful information: I was able to find a duplicate board on amazon for $52.
I now have air conditioning and more knowledge than I need about rooftop ac. Thanks to Ray for his attempt at pointing me in the right direction. At least I had a clue after I knew where the caps were.