Electrical Checks - Sony MHC-V41D Service Manual

0 dB = 1 V
TUNER SECTION
FM AUTO STOP CHECK
signal
generator
Procedure:
1. Press the [ ] button to turn the power on.
1
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: Use 75 ohm coaxial cable to connect signal generator and the unit.
You cannot use video cable for checking.
Use signal generator whose output impedance is 75 ohm.
3. Press the [FUNCTION] button to select the "TUNER FM"
function and scan the input FM signal with automatic scan-
ning.
4. Confi rm that input frequency of A, B and C detected and auto-
matic scanning stops.
When the station signal is received in good condition, automatic
scanning stops.
SECTION 4

ELECTRICAL CHECKS

unit
DVD/CD SECTION
Note:
1. DVD/CD block is basically constructed to operate without adjustment.
2. Use YEDS-18 disc (Part No. 3-702-101-01) unless otherwise indicat-
ed.
3. Use an oscilloscope with more than 10 M impedance.
4. Clean the object lens by an applicator with neutral detergent when the
signal level is low than specifi ed value with the following check.
RF SIGNAL CHECK
MOTHER 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 MOTHER board.
2. Press the [ ] button to turn the power on.
1
3. Press the [FUNCTION] button to select the "DVD/CD" func-
tion.
4. Press the [ ] button to open the disc tray and set the disc
Z
(YEDS-18).
5. Press the [ ] button to close the disc tray.
Z
6. Press the [ ] button to playback.
N
7. 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.
Connection Location:
– MOTHER Board (Side A) –
IC109
MHC-V41D
oscilloscope
(DC range)
+
–
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.0 ± 0.25 Vp-p
IC2001
CN302
pin 1 (GND)
pin 17 (RF)
37