Dell E1709W - DC 12 V and 5 V Output Circuit and Feedback; I;F Board Circuit

Service Manual
10
When Q850 are turned off, the main current flow will be consumed through D851, C875, R854
and D853. This will prevent Q850 from being damaged under large current impulse and voltage
spike.
2.2.4) DC_12V and 5V Output Circuit and Feedback circuit :( fig.7)