Electrical Adjustmens - Sony D-FS18 Service Manual

D-FS18
CD SECTION
The CD section adjustments are done automatically in this set.
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 : Minimum
AVLS : NORM
HOLD : OFF
8
SECTION 4
ELECTRICAL ADJUSTMENTS
(J401)
Focus bias Check
Condition:
• Hold the set in horizontal state.
• Terminate TAP802 (open) by solder.
Connection:
Oscilloscope
(AC range)
2 K Ω
TJ629 (RF)
TJ635 (GND)
[MAIN BOARD] (Side B)
Procedure:
1. Connect the oscilloscope to the test points TJ629 (RF) and TJ635
(GND) on the MAIN 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 : 500ns
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.
RF level
0.4 to 0.5 Vp-p