CDX-T70MX (serv.man2) - Sony Car Audio Service Manual (repair manual). Page 17

17

17

GND

+

BUS cable

compact disc changer

master unit

power supply

(DC 14.4 V)

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

when indicated.

4. Use a master unit that supports SONY bus system.

Procedure:
1. Connect the oscilloscope to TP (RFAC) 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-

nal level is correct or not.

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.

RF signal waveform

VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(10 : 1 probe in use)

level: 1.4 

+ 0.3

 Vp-p

– 0.4

oscilloscope

(AC range)

+
–

TP (VC)

TP (RFAC)

IC101

Procedure:
1. Connect the oscilloscope to TP (TE) and TP (VC) on the RF

board.

2. Put the set into play mode by loading the disc (YEDS-18).
3. Press the 

[        AMS        ]

 button on the master unit, and check

the traverse waveform*.

4. Confirm that the oscilloscope waveform is symmetrical on the

top and bottom in relation to 0 V dc, and check this level.

* Traverse waveform: This is the tracking error wave form appears

when crossing the track.

.        >

oscilloscope

(DC range)

+
–

TP (TE)

TP (VC)

IC101