My trane XL 1200 is 10 years old. After a power outage for 13 days, the outside unit would hum, but the fan won't turn. In the attic, the green light on the air handler was blinking more than once per second. We replaced the start/run capacitor and now the outside unit won't come on at all and there is a red light that comes on in the air handler and the former green light is now solid green. Any ideas?

I would safely override Compressor contactor and see if fan and compressor kick in, if not, I would repair/replace fan and/or compressor. Does fan spin freely?

Yes, the fan spins freely.

When you override the compressor contactor, Does the Fan Or Compressor work? And can you tell which is humming.

The compressor works, but the fan does not. The fan spins freely when I spin it manually, though, if that makes a difference. Thanks so much for your help!

I a capacitor does not help fan, you need a new motor. Be sure it is blowing up, if not you need to swap 2 wires.

Thanks for all of your help.

Good Luck, let us know how you do.