Sony SCD-XB770 Service Manual page 24

SCD-XB770
Ver 1.1 2001.07
4-7. WAVEFORMS CHECK
This set performs automatic adjustment for each disc, and there-
fore the set need not be adjusted when parts are replaced, but it
requires checking following the description in this section, 4-1.
IC AND FLUORESCENT DISPLAY TUBE CHECK and 4-2.
AUTO CHECK.
For the check, the test mode is used. Wrong setting causes a trouble,
thus requiring extreme care.
BU Electrical Adjustment Mode
The BU electrical adjustment mode is used to check the S curve
waveform, traverse waveform and RF waveform. After a disc is
placed on the tray, each time the
the check mode is switched in order for S curve waveformt
traverse waveformtRF waveform.
Setting Method:
After setting the test mode, rotate the
"9C BU DENCHO" and press the
"BU MEASURE" will be displayed if the BU electrical adjust-
ment mode becomes active.
S Curve Check
Connection:
MAIN board
TP506 (FE)
TP504 (AVC)
Checking Method:
1. After setting the BU electrical adjustment, place the test disc
(PATD-012 or SATD-S5 or SATD-S4) on the tray and close
[
the tray, then press the l
2. At the completion of disc type check, "CD DETECT" will be
displayed (for PATD-012 or YEDS-18).
Note: For the SATD-S5 or SATD-S4, "SACD DETECT" is displayed.
[ AMS
3. Press again the l
check mode will become active and "S-CURVE MODE" will
be displayed.
4. Connect an oscilloscope to the TP506 (FE) and TP504 (AVC)
on the MAIN board.
5. Check that the level A and B of waveform on the oscilloscope
satisfy the specification.
Specified Value:
Disc
SATD-S5 or
SATD-S4
0.7 to 1.7 Vp-p
PATD-012 or
YEDS-18
S curve waveform
VC
Note: For easier observation of this waveform, extend the sweep time
and raise the brightness.
Checking and Connecting Location : See page 25.
24
[ AMS ]
l L dial is pressed,
[ AMS ]
l L dial to select
[ AMS ]
l L dial to enter.
oscilloscope
+
–
AMS ]
L dial.
]
L dial, and the S curve waveform
A B
- 0.1 to +0.1V
A
Traverse Check
Connection:
MAIN board
TP513 (TE)
TP504 (AVC)
Checking Method:
1. Under the condition of S curve waveform check mode in step
[
5, press the l
2. After "WAIT" is displayed, the traverse waveform check mode
will become active and "TRAVERSE MODE" will be dis-
played.
3. Connect an oscilloscope to the TP513 (TE) and TP504 (AVC)
on the MAIN board.
4. Check that the level A and B of waveform on the oscillo-
scope satisfy the specification.
Specified Value:
Disc
SATD-S5 or
SATD-S4
PATD-012 or
YEDS-18
Traverse waveform
VC
Checking and Connecting Location : See page 25.
B
oscilloscope
+
–
AMS ]
L dial.
A
0.9 to 1.4 Vp-p
- 0.1 to +0.1V
Center fo the waveform
A
B
B