Read Harman Kardon FL 8550 (serv.man13) Service Manual online
Circuit Description
1. RF AMP BLOCK
The KA9220 is designed for 3-spot type optical pick-up assembly. The photo detector is composed of 6
light sensor (A through F). The photo detector A, B, C and D detect audio modulation signal on the disc
and generate focus error signal.
RF I-V AMP (1) and RF I-V AMP (2) are converted current of PD1 (A + C) and PD2 (B + D) through the
58 Kohm Internal resistor into Voltage.
Furthermore, they are added to RF Summing amplifier.
This signal (A + B + C + D) is outputted from RFO (Pin66).
The output Voltage is as follow.
)
iPD2
iPD1
(
X
R3
V
RFO
+
−
=
)
R2
V
R1
V
(
X
R3
B
A
+
−
=
)
10K
V
10K
V
(
22K X
-
B
A
+
=
)
V
V
(
X
2.2
-
B
A
+
=
FL8550
14
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