Read Sony ICF-CD873 Service Manual online
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CD SECTION
Note:
Tracking Balance Adjustment and Tracking Gain Adjustment are
done automatically in this set.
Tracking Balance Adjustment and Tracking Gain Adjustment are
done automatically in this set.
TEST MODE
1. Press the CD LID OPEN/CLOSE DET switch (S424) on the
PUSH SWITCH board.
2. Under standby condition (when the clock appear in the dis-
play), short the BP (CD TEST AUTO).
Note:
If the power is supplied to the microprocessor once, it is backed up
for 3 minutes, therefore the TEST mode will not be activated within
3 minutes even if the power is turned on again. In this case, short
instantaneously the BP (CD TEST MANUAL).
3 minutes even if the power is turned on again. In this case, short
instantaneously the BP (CD TEST MANUAL).
3. Press the ^ key, and the focus search is repeated.
At this time, check that the optical pick-up objective lens moves
smoothly without a sticking or noise.
smoothly without a sticking or noise.
4. Load the test disc (YEDS-18: Part No. 3-702-101-01), and per-
form automatic adjustment after the focus search succeded.
5. After automatic adjustment is finished, move the sled motor
to the center. At this time, keep pressing the + and =
keys to confirm that optical pick-up moves smoothly via most
inside track
keys to confirm that optical pick-up moves smoothly via most
inside track
→
most outside track
→
most inside track with-
out a sticking or noise.
6. Confirm the traverse waveform.
7. Press the [WAKE UP TRACK] key.
8. The tracking servo and the sled servo are turned on, the mute
7. Press the [WAKE UP TRACK] key.
8. The tracking servo and the sled servo are turned on, the mute
is cancelled.
9. Playback the 2nd track.
10. Adjust the RF and jitter waveforms.
10. Adjust the RF and jitter waveforms.
Connecting points: MAIN Board (See page 13)
Focus Bias Adjustment
This adjustment is to be done when the optical block is replaced.
Connection:
Adjustment Procedure:
1. Connect the oscilloscope to TP504 (VREF) and TP503 (RF)
1. Connect the oscilloscope to TP504 (VREF) and TP503 (RF)
on the MAIN board.
2. Insert the test disc (YEDS-18: Part No.3-702-101-01) and press
^ key to play.
3. Move the optical pick-up to the music area on the disc to en-
able easy visibility of the eye pattern by + or = key
pressing.
pressing.
4. Adjust RV501 so that the oscilloscope waveform is as shown
in the figure below (eye pattern).
A good eye pattern means that the diamond shape (≈) in the
center of the waveform can be clearly distinguished.
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)
Adjustment Location: MAIN Board (See page 13)
MAIN board
TP503 (RF)
TP504 (VREF)
+
–
–
oscilloscope
(AC range)
VOLT/DIV: 0.2 V
TIME/DIV: 500 ns
TIME/DIV: 500 ns
1.3
±
0.5 Vp-p
When observing the eye pattern, set the oscilloscope
for AC range and raise vertical sensitivity.
for AC range and raise vertical sensitivity.
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