Is it repirable? Perhaps
A quiet hum suggests the blower motor did not start
This can be caused by one of two or three things but the hum rules out the third (Wiring issue)
Bad Motor Start/Run Capicator.. this is about 20 -30 bucks plus labor unless you replace it yourself
Bad blower motor 200-300 plus labor
Now the other motor up there is the compressor.. repair on that one. you might as well replace the entire upper unit.
OH one more possible issue So Something obstructing the fan or blower can also cause non-op But odds are low.