Sony HCD-MD373 Adjusting Points And Connecting Points, Cd Section, Bd Md Board Side A, Procedure

5-15. ADJUSTING POINTS AND CONNECTING POINTS

[BD (MD) BOARD] (SIDE A)

CN101

D101

CN110 GND

I+3V

IOP

TE

RF

VC

NOTE

IC171

[BD (MD) BOARD] (SIDE B)

IC101

IC121

IC192

NOTE:It is useful to use the jig. for checking the waveform. (Refer to Servicing Note on page 11.)

CD SECTION

Note:

1.CD Block is basically constructed to operate without adjustment. Therefore, check each item in order given.

2.Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.

3.Use an oscilloscope with more than 10MΩ 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.

S Curve Check

oscilloscope

BD (CD) board
TP (FE)	+
TP (VC)	–

Procedure :

1.Connect the oscilloscope to test points TP (FE) and TP (VC).

2.Connect TP (FEI) and Ground, and TP (AGCCON) and Ground of the BD board with lead wires.

3.Press the 1/u button to turn the set ON.

4.With the disc (YEDS-18) loaded, press the ^ (CD) button and perform focus search. (Focus search will be performed in the same way even while the disc table is pushed in and out.)

5.Check the symmetry and peak to peak level of the oscilloscope waveform (S curve) at this time.

S-curve waveform

symmetry

A

Within 4 ± 1 Vp-p

B

6. After check, remove the lead wire connected in step 2.

Note: • Try to measure several times to make sure than the ratio of A : B or B : A is more than 10 : 7.

•Take sweep time as long as possible and light up the bright- ness to obtain best waveform.

Checking Location : BD (CD) board

RF Level Check

oscilloscope

BD (CD) board
TP (RF)	+
TP (VC)	–

Procedure :

1.Connect oscilloscope to test point TP (RF) and TP (VC) on BD board.

2.Connect TP (AGCCON) and Ground of the BD (CD) board with lead wires.

3.Press the 1/u button to turn the set ON.

4.Put disc (YEDS-18) in and playback 5track.

5.Confirm that oscilloscope waveform is clear and check RF sig- nal level is correct or not.

6.After check, remove the lead wire connected in step 2.

Note: Clear RF signal waveform means that the shape “ ◊” can be

clearly distinguished at the center of the waveform.

RF signal waveform

VOLT/DIV : 200mV

TIME/DIV : 500ns

level : 1.45 ± 0.3 Vp-p

Checking Location : BD (CD) board

E-F Balance (1 Track Jump) check

oscilloscope

BD (CD) board
TP (TE)	+
TP (VC)	–

Procedure:

1.Connect oscilloscope to test point TP (TE) and TP (VC) on BD (CD) board.

2.Press the 1/u button to turn the unit ON.

3.Put disc (YEDS-18) in to play the number five track.

4.Press the ^(CD) button.

5.Check the level B of the oscilloscope's waveform and the A (DC voltage) of the center of the Traverse waveform.

Confirm the following:

•A/B x 100 = less then ± 22 (%)

•B = 1.3 ± 0.6 Vp-p

1 track jump waveform Center of the waveform

B

A (DC voitage)

0V

Symmetry

level : 1.3 ± 0.6 Vp-p

Checking Location : BD (CD) board

Checking Location : BD (CD) board [ BD (CD) BOARD ] — SIDE B —

TP (VC)

TP IC103 (RF)

TP (AGCCON)

TP (FE)

TP

(TE) TP (FEI)

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