Electrical Check - Sony MHC-V73D Service Manual

MHC-V73D
TUNER SECTION
FM AUTO STOP CHECK
set
Procedure:
1. Turn the power on.
2. Input the following signal from Signal Generator to FM
antenna input directly.
Carrier frequency : A = 87.5 MHz, B = 98 MHz, C = 108 MHz
Deviation : 75 kHz
Modulation : 1 kHz
ANT input : 35 dBu (EMF)
Note: Please use 75 ohm "coaxial cable" to connect SG and the
set. You cannot use video cable for checking.
Please use SG whose output impedance is 75 ohm.
3. Set to FM tuner function and scan the input FM signal with
automatic scanning.
4. Confi rm that input Frequency of A, B and C detected and
automatic scanning stops.
The stop of automatic scanning means "The station signal is
received in good condition".
27

ELECTRICAL CHECK

0 dB = 1 V
signal
generator
+
75
–
SECTION 4
FOCUS BIAS CHECK
MOTHERBOARD board
CN302 pin 17 (RF)
CN302 pin 1 (GND)
Procedure:
1. Connect the oscilloscope to CN302 pin 17 (RF) and CN302 pin
1 (GND) on the MOTHERBOARD board.
2. Press the [
1
[FUNCTION] touch key to select DVD/CD function.
3. Set the test disc (CD: YEDS-18) on the tray and touch [N]
touch key to playback.
4. Confi rm that oscilloscope waveform is as shown in the fi gure
below (eye pattern).
A good eye pattern means that the diamond shape () in the
center of the waveform can be clearly distinguished.
Checking Location:
-MOTHERBOARD Board (Component Side)-
pin 17 (RF)
Sony CONFIDENTIAL
For Authorized Servicer
oscilloscope
(DC range)
+
–
] button to turn the power on, and touch the
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.1 ± 0.25 Vp-p (DVDSL)
1.0 ± 0.25 Vp-p (CD)
CN302
pin 1 (GND)
SYS SET