Feedback Circuit - Sony HS75 Service Manual

Feedback circuit:

Alternating voltage exists at the two terminals of R842 when the loads are working. After being commuted
and filtered, it changed to a DC sampling voltage. Apply the voltage to PIN8 of U801, and it is used to control
the duty of pulse output. The whole process acts as steadying the output voltage.
PIN8 of U801
ISEN
R808
2K 1/16W
R809 D802
220 1/16W 2
1
BAV99
37
CN802
1
2
R842
3 CONN
1K 1/10W
HS75 Sony