Read Sony CDX-646 / CDX-646X Service Manual online
14
SECTION 5
ELECTRICAL CHECK
Note:
1. This check is performed with the set placed horizontally.
2. Power supply voltage: DC14.4 V (more than 3 A).
3. Be sure to use the disc “YEDS-18” parts code: 3-702-101-01, but only
2. Power supply voltage: DC14.4 V (more than 3 A).
3. Be sure to use the disc “YEDS-18” parts code: 3-702-101-01, but only
when indicated.
Connection:
Focus Bias Check
Connection:
– RF Board (Component Side) –
Procedure:
1. Connect the oscilloscope to TP (RFO) and TP (VC) on the RF
1. Connect the oscilloscope to TP (RFO) and TP (VC) on the RF
board.
2. Put the set into play mode by loading the disc (YEDS-18).
3. Confirm that oscilloscope waveform is clear and check RF sig-
3. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
Note:
Clear RF signal waveform means that the shape “
◊
” can be clearly distin-
guished at the center of the waveform.
When observing the eye pattern, set the oscilloscope to AC range
and raise the vertical sensitivity so that it may be easily seen.
and raise the vertical sensitivity so that it may be easily seen.
GND
+
BUS cable
compact disc changer
master unit
CONTROL connector
(CN901)
(CN901)
power supply
(DC 14.4 V)
oscilloscope
(AC range)
+
–
–
TP (VC)
TP
(RFO)
IC101
RF signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(10 : 1 probe in use)
TIME/DIV: 500 ns
(10 : 1 probe in use)
level: 1.4
±
0.3 Vp-p
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