Read Harman Kardon HD 755 (serv.man9) Service Manual online
FUNCTION DESCRIPTION
Tracking System
The tracking error output of E and F is given to Pin 25 (TEOUT). C8 is required for
oscillation-proof. R10 is chosen such that TEOUT of Pin 25 become 1.4Vp-p.
During alignment procedure, the DSP IC (MN662790) will adjust the tracking balance
voltage V
TBAL
from Pin 31. V
TBAL
varies with reference to the center voltage V
REF2
(=1.65 V)
within
±
0.5 V.
The tracking gain will change according to the type of disc. For normal disc or CDR disc,
V
GCTRL
is set to V
REF2
; for CDRW disc V
GCTRL
is set to V
REF2
- 0.75 V. At the same time, the
focus gain is changed too.
A
B
C
D
F
PDIC
E
32
31
28
21
30
23
25
24
GCTRL
To Focus System
TBAL
Subtraction
R10
TEN
C8
TEOUT
V
GCTRL
C2
C15
C5
R5
V
REF1
V
REF2
R15
R14
V
TBAL
11
HD755
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