Read Harman Kardon FL 8370 (serv.man4) Service Manual online
FL8370
1.3 Tracking Error Amp
The optical currents detected from the side photo diode (E and F) pf pick-up are inputted to the E and F
pin and converted into voltage signals by E I-V and F I-V amp. The output of tracking error amp
generates the difference between E I-V AMP and F I-V AMP voltage output.
The E-F balance can be adjusted by modifying the gain of E I-V AMP, and the tracking gain
can be adjusted automatically by controlling the peak voltage at pin TE2 by micom program.
pin and converted into voltage signals by E I-V and F I-V amp. The output of tracking error amp
generates the difference between E I-V AMP and F I-V AMP voltage output.
The E-F balance can be adjusted by modifying the gain of E I-V AMP, and the tracking gain
can be adjusted automatically by controlling the peak voltage at pin TE2 by micom program.
Figure 6. Tracking error amp circuit
1.4 Focus OK Circuit
The FOK is the output. The focus OK circuit generates a timing window to enable focus servo operation
from focus search status. When the difference of the RFO (pin74)signal and DC coupled signal
IRF(pin75) are above the predefined voltage the Focus OK circuit output (pin40) becomes active(High
output). The predefined voltage is -0.39V
from focus search status. When the difference of the RFO (pin74)signal and DC coupled signal
IRF(pin75) are above the predefined voltage the Focus OK circuit output (pin40) becomes active(High
output). The predefined voltage is -0.39V
Figure 7. Focus OK circuit
67
-
+
68
79
I-V AMP
I-V AMP
54
55
Balance
F
E
EI
GAIN_UP/DOWN
BAL < 4 : 0 >
GAIN < 3 : 0 >
TE1
LPFT
To ISTAT
1
3
K
7
5
K
2
2
0
K
1
1
0
K
5
6
K
2
7
K
1
3
K
1
6
K
7
.5
K
3
.3
K
1
.5
K
-
53
TE2
Window Comp
Gain
Window Comp
Window Comp
To ISTAT
To TRCNT
74
75
-
+
-
+
40
RFO
IRF
FOK
40K
40K
40K
57K
90K
VC+0.625V
12
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