Philips ST-D777ES, Руководство по обслуживанию

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4-2. CIRCUIT BOARDS LOCATION
• Waveforms
MAIN board
• U : B+ Line.
•
V
: B– Line.
• Voltages and waveforms are dc with respect to ground under
no-signal (detuned) conditions.
no mark : FM
( ) : MW
< > : LW
∗
: Impossible to measure
• Voltages are taken with a VOM (Input impedance 10 M
Ω
).
Voltage variations may be noted due to normal production tol-
erances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production tol-
erances.
• Circled numbers refer to waveforms.
• Signal path.
F
: FM
f
: AM
For printed wiring boards.
Note:
• X
: parts extracted from the component side.
• b : Pattern from the side which enables seeing.
Note:
The components identified by mark
0
or dotted line with
mark 0 are critical for safety.
Replace only with part number specified.
• Indication of transistor
C
These are omitted
E B
THIS NOTE IS COMMON FOR PRINTED WIRING
BOARDS AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed in
each block.)
For schematic diagrams.
Note:
• All capacitors are in µF unless otherwise noted. pF: µµF 50 WV
or less are not indicated except for electrolytics and tantalums.
• All resistors are in
Ω
and 1 /
4
W or less unless otherwise speci-
fied.
•
f
: internal component.
•
C
: panel designation
AC SW board
KEY SW board
POWER board
DISPLAY board
ENCODER board
MAIN board
1
IC201 wf
4.6Vp-p
222.2ns
2
IC401
qf
2.2Vp-p
230.8ns
3
IC501
rg
3.3Vp-p
40.7ns
4
IC502 qd
6.0Vp-p
20.3ns
5
IC502 ta
5.6Vp-p
40.7ns
6
IC502
tf
6.0Vp-p
162.7ns
7
IC601
yk
3.5Vp-p
100.0ns