SONY CDX838
Instrukcja Serwisowa

SECTION 6 ELECTRICAL ADJUSTMENTS
Note: 1. Perform adjustments as given. 2. Power supply voltage: DC14.4 V (more than 3A).

� TRACKING OFFSET CHECK � RF BOARD (Conductor Side) �
oscilloscope CNJ12 + � BP11 (TE) TP (VC)

� FOCUS GAIN ADJUSTMENT (COARSE ADJUSTMENT) This adjustment is to be performed when replacing the following parts. � Optical Pick-up Block � RV14 � RF BOARD (Conductor Side) �
CNJ12

� When gain is lowered... The set does not play because of no focus operation. � When gain is highered... Operation noise is heard due to a scratch or a dust, then operation will be unstable.

� FOCUS BIAS CHECK � RF BOARD (Conductor Side) �
oscilloscope CNJ12 TP (RF) + �

IC51

TP (VC) IC11

Procedure: 1. Connect the oscilloscope to BP11 (TE) and TP (VC) on the RF board. 2. Put the set into play mode by loading the disc. 3. Press the . AMS > button, 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.

RV14

IC51

IC11

IC11

Procedure: 1. Connect the oscilloscope to TP (RF) and TP (VC) on the RF board. 2. Put the set into play mode by loading the disc. 3. Confirm that oscilloscope waveform is clear and check RF signal level is correct or not.
Note: Clear RF signal waveform means that the shape ��� can be clearly distinguished at the center of the waveform.

Procedure: 1. Set RV14 (RF board) to the standard position. 2. Check that there is not an abnormal amount of operation noise (white noise) from the 2-axis devise. If there is, turn RV14 slightly clockwise. � RF BOARD (Conductor Side) �

IC51

Traverse waveform VOLT/DIV : 500 mV TIME/DIV : 2 ms Center : 0 V

RF signal waveform VOLT/DIV: 200 mV TIME/DIV: 500 ns level: 1.4 ± 0.3 Vp-p
A=B A 0V B

MIN side (low gain)

traverse waveform (100 track jump waveform)
MAX side (high gain)

RV14 standard position

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