Electrical Adjustments - Sony D-FJ75TR Service Manual

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.
VOLUME button : Minimum
AVLS switch : NORM
HOLD switch : OFF
Checking Location:
– MAIN board (Side A) –
TP 629 (RF)
TP 635 (AGND)
SECTION 4

ELECTRICAL ADJUSTMENTS

Focus bias Check
Condition:
• Hold the set in horizontal state.
Connection:
Procedure:
1. Connect the oscilloscope to the test points TP629 (RF) and
2. Set a disc. (YEDS-18)
3. Press the
4. Check the oscilloscope waveform is as shown below.
RF Signal reference Waveform (Eye Pattern)
5. Stop revolving of the disc motor by pressing the
— 6 —
MAIN board
TP629 (RF)
TP635 (AGND)
TP635(AGND) on the MAIN board.
button.
u
A good eye pattern means that the diamond shape (◊) in the
center of the waveform can be clearly distinguished.
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.
oscilloscope
(AC range)
2 k Ω
+
–
RF level
0.35 to 0.65 Vp-p
x button.