Sony CD Walkman D-EJ855, Руководство по обслуживанию

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D-EJ855
9 9
SECTION 4
ELECTRICAL CHECK
The CD section adjustments are done automatically in this set.
In case of operation check, confirm that focus bias.
Precautions for Check
1. Perform check in the order given.
2. Use YEDS-18 disc (Part No.: 3-702-101-01) unless otherwise
indicated.
3. Power supply voltage requirement: DC4.5 V in DC IN jack.
(J401)
VOLUME : Minimum
AVLS switch : NORM
HOLD switch : OFF
G•PROTECTION switch : 1
Connecting and Checking Location:
– MAIN Board (Component Side) –
Focus bias Check
Condition:
• Hold the set in horizontal state.
Connection:
Procedure:
1. Connect the oscilloscope to the test points TP601 (RF) and
TP418 (GND) on the MAIN board.
2. Set a disc. (YEDS-18)
3. Press the
> N button.
4. Check the oscilloscope waveform is as shown below.
A good eye pattern means that the diamond shape (
◊
) in the
center of the waveform can be clearly distinguished.
RF Signal reference Waveform (Eye Pattern)
VOLT/DIV : 100 mV (With the 10:1 probe in use)
TIME/DIV : 500 ns
To watch the eye pattern, set the oscilloscope to AC range and
increase the vertical sensitivity of the oscilloscope for easy watch-
ing.
5. Stop revolving of the disc motor by pressing the x button.
oscilloscope
(AC range)
+
–
MAIN board
TP601 (RF)
TP418 (GND)
2 k
Ω
RF level
0.4 to 0.6 Vp-p
C404
D403
KA
R305
R489
VDR304
VDR303
R410
C301
CN503
C449
+
R604
R601
R603 C601
C603
R602
C
606
C
605
C448
C604
55
C454
C453
R469
C452
FB101
VDR101
VDR201
FB301
FB201
R303
R304
C102
C202
R102
R202
R101
R201
1
12
24
13
IC404
VDR301
J301
LINE OUT
(OPTICAL)
1
15
OPTICAL
PICK-UP
BLOCK
DAX-25E
TP601 (RF)
TP418
(GND)