Electrical Checking - Sony D-NE20 Service Manual

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The CD section adjustments are done automatically in this set.
In case of operation check, confirm that RF level.
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 : DC1.5V in battery termi-
nals.
VOLUME button : Minimum
HOLD switch
Checking Location:
[EGH BOARD] (SIDE B)
TP608
(RF)
IC604
TP602
(GND A)
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L 13942296513
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ELECTRICAL CHECKING

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SECTION 4
2 9
8
RF Level Check
Condition:
• Hold the set in horizontal state.
Connection:
EGH board
TP608 (RF)
TP602 (GND A)
Procedure:
1. Connect the oscilloscope to the test points TP608 (RF) and
TP602 (GND A) on the EGH board.
2. Set a disc. (YEDS-18)
3. Press the u 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
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3 6 7 1 3 1 5
To watch the eye pattern, set the oscilloscope to AC range and
increase the vertical sensitivity of the oscilloscope for easy
watching.
5. Stop revolving of the disc motor by pressing the x button.
co
.
D-NE20/NE20LS
9 4 2 8
Oscilloscope
(AC range)
2 k Ω
+
–
0 5 8 2 9 9 4 2 8
RF level
0.55 to 0.6 Vp-p
m
9 9
9 9
11