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37

INTRODUCTION
When set to the test mode performed in 

,

when the tape is rewound after recording, the “REC memory

mode” which rewinds only the recorded portion and playback is
set.
This “REC memory mode” is convenient for performing this ad-
justment. During recording, the input signal FUNCTION will auto-
matically switch to VIDEO.
(After recording, press the  m  button without stopping will re-
turn to the position where recording was started.)

1. Press  FUNCTION  button to select VIDEO. (This step is not

necessary if the above test mode has already been set.)

2. Insert a tape into deck B, press the  REC PAUSE/START  button,

and then press the  H  button to start recording.

3. Mode: Record

5. Confirm playback the signal recorded in step 2 become adjust-

ment level as follows.
If these levels do not adjustment level, adjust the RV341 (L-CH)
and RV441 (R-CH) on the AUDIO board to repeat steps 3 and 4.

Adjustment level: The playback output of 10 kHz level difference

against 315 Hz reference should be 0 ± 0.5 dB.

Adjustment Location: AUDIO board

INTRODUCTION
When set to the test mode performed in 

, when the tape is rewound after recording, the “REC memory

mode” which rewinds only the recorded portion and playback is
set.
This “REC memory mode” is convenient for performing this
adjustment. During recording, the input signal FUNCTION will
automatically switch to VIDEO.
(After recording, press the  m  button without stopping will re-
turn to the position where recording was started.)

1. Press  FUNCTION  button to select VIDEO. (This step is not

necessary if the above test mode has already been set.)

2. Insert a tape into deck B, press the  REC PAUSE/START  button,

and then press the  H  button to start recording.

3. Mode: Record

4. Mode: Playback

5. Confirm playback the signal recorded in step 2 become adjust-

ment level as follows.
If these levels do not adjustment level, adjust the RV301 (L-CH)
and RV351 (R-CH) on the MAIN board to repeat steps 3 and 4.

Adjustment level:
CN301 playback level: 47.2 to 53.0 mV (–24.3 to –23.3 dB)

Adjustment Location: MAIN board

4. Mode: Playback

1

3

Ω

Ω

1

3

38

Note :

1. CD Block is basically designed 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 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.

Procedure :
1. Connect oscilloscope to TP (FEO).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (GND) by lead wire.
4. Turn Power switch on.
5. Load a disc (YEDS-18) and actuate the focus search. (In

consequence of open and close the disc tray, actuate the focus
search)

6. Confirm that the oscilloscope waveform (S-curve) is

symmetrical between A and B. And confirm peak to peak level
within 4 ±1 Vp-p.

7. After check, remove the lead wire connected in step 2 and 3.

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

brightness to obtain best waveform.

Procedure :
1. Connect oscilloscope to TP (RF).
2. Connect between TP (AGCCON) and TP (GND) by lead wire.
3. Turned Power switch on.
4. Load a disc (YEDS-18) and playback.
5. Confirm that oscilloscope waveform is clear and check RF signal

level is correct or not.

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

±

Clear RF signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

RF signal waveform

Procedure:
1. Connect oscilloscope to TP (TEO) and TP (VC) board.
2. Turned Power switch on.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the  u  button. (Becomes the 1track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscilloscope

waveform.

1 track jump waveform

Specification level:      

x

 100=less than ±22%

6. After check, remove the lead wire connected in step 1.

Procedure :
1. Connect frequency counter to test point (XPCK) with lead wire.

2. Turned Power switch on.
3.

Put the disc (YEDS-18) in to play the number five track.
Confirm that reading on frequency counter is 4.3218MHz.

±

±

A

B

39

[ BD (CD) BOARD ] — SIDE B —

40

If malfunctions caused by Optical pick-up such as sound skipping are suspected, follow the following check.

Other faults are suspected.
Check the threading mechanism, etc.

Start

NG

NG

NG

OK

OK

OK

Laser Power Check

6-6-2.

(See page 43)

6-6-3.

(See page 43)

6-6-4.

(See page 44)

Iop Compare

Auto Check

Replace Optical pick-up or MDM-7B