820-00850 fan at max rpm and only one is spinning

[nininunz]

Titles says it. When I turn the board on one fan kicks up to max speed immediately. The other does absolutely nothing. Was fixing an audio issue around U6400 but cannot say whether or not that's when it started. I can confirm once upon a time the board worked fine though. Not sure if it was damaged from being in a pile or from me fixing audio.

Edit:
FAN_RT_PWM - 4.88v
FAN_LT_PWM - 0v

Replace Q6000 or is it something else?

 

[2informaticos]

Compare diode mode to ground readings between Q6000/50 areas.
Check for knocked off component, or broken trace.