Samsung MAX-805 Service Manual page 19

Special Circuit Descriptions
5-1-3 Tracking Error Amp
The current signals from the side spot photo diode (E and F) are input 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 is due to the difference between
E 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(Pin TE1) can be
adjusted automatically by micom program.
5-1-4 Focus OK Circuit
Extracting the DC part of RFI and RFO and comparing with the basic DC level, if RF Level is more than basic
level, the FOK is output. The focus OK circuit generates a timing window of focus on to monitor the focus
search status of focus serve.
5-2
67 IV AMP
F
-
+
68
IV AMP
E
TGFI GAIN - UP/DOWN
EI
79
BAL< 4 0 >
GAIN< 3 : 0 >
from Digital
40K
40K
74
-
75 +
40K
LPFT
TE1
54 55
WIN COMP
-
To ISTAT,TRCNT
WIN COMP
57K
-
+
90K
VC+0.625V
BALL
BALH
TGL
TGH
40 FOK
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