BMZ-K7D, CX-BK7 - Sony Audio Service Manual (repair manual). Page 37

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1. The adjustment should be performed with the rated power sup-

ply voltage.

2. The adjustments should be performed for both L-ch and R-ch.

0 dB = 0.775 V

1.

DVD block  is basically designed to operate without adjustment. There-
fore, check each item in order given.

2.

Use DVD reference disc unless othermise indicated.
[DVD reference disc]
TDV-520CSO (DVD-SL): PART No. J-2501-236-A
LUV-P01 (CD):

PART No. 4-999-032-01

TDV-540C (DVD-DL):

PART No. J-2501-235-A

 Do not use existing test disc for DVD.

3.

Use an oscilloscope with more than 10M

Ω

 impedance.

4.

Clean the object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.

After parts related to the servo circuit (RF amplifier (IC001), DSP
(IC509), motor driver (IC501), EEPROM (IC903) so on) are re-
placed, re-adjusting the servo circuit is necessary. Select “ALL” at
“1. DRIVE AUTO ADJUSTMENT” (Refer to page 30 in TEST
MODE) and adjust DVD-SL (single layer), CD and DVD-DL (dual
layer).

Purpose:
This adjustment is made to satisfy the NTSC standard, and if not
adjusted correctly, the brightness will be too large or small.

Procedure:
1. Connect an oscilloscope to MONITOR VIDOE OUT jack

(J802) on the SP board.

2. Load a DVD reference disc.
3. Check the video signal level is 1.00 

±

 0.05Vp-p.

SP board
MONITOR VIDEO OUT
 jack (J802)

75 

Ω

Oscilloscope

set

1.00 

±

 0.05 Vp-p

(WHITE 100%)

Procedure:
1.

Record mode

2.

Mode:  Playback
i-Bass OFF
BASS 0
TREBLE 0

3.

Confirm playback the signal recorded in step 1 become
adjustment level as follows.

4.

If these levels do not adjustment level, adjustment the SFR452
(L-ch) and SFR451 (R-ch) to repeat steps 1 and 4.

Adjustment level: Playback output of 315 Hz to playback out-

put of 10 kHz:  0 

±

 1.0 dB (0 

±

 4.5mV).

Adjustment Location: DECK board

+
–

set

recorded
portion

SP board
FRONT SPEAKER
terminal (JK502)

level meter

attenuator

set

MAIN board
MD (AUX) IN jack (JK602)

1) 315 Hz
2) 10 kHz

50 mV (–23.8 dB)







600 

Ω

blank tape
CN-123

AF OSC

SFR451

REC Bias

Adjustment

(R-ch)

SFR452

REC Bias

Adjustment

(L-ch)

Procedure:
1.

Connect an oscilloscope to test point 1 pin and 3 pin 
of CN901 on the MB03 board.

2.

Turn the power on.

3.

Put the disc (LUV-P01) (Part No.:4-999-032-01) (CD)  
in to playback.

4.

Conf

5.

Put the disc (TDV-520CSO) (Part No.:J-2501-236-A) 
(DVD) in to playback.

6. Perform confirmation in the same manner as step 4.

irm that oscilloscope waveform is clear and check RF

signal level is correct or not.

A clear RF signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

       RF signal waveform

VOLT/DIV: 200 mV
TIME/DIV: 500 ns 

CD: 1.05 

±

 0.2 Vp-p

DVD: 1.09 

±

 0.2 Vp-p

+
–

oscilloscope

CN901 

1

 pin

CN901 

3

 pin

MB03 board

CN901

1

7