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– 17 –

6

bearing (SL)

5

feed screw ass’y

3

screw
(K2 

×

 3)

2

shaft (SL2)

1

two screws
(K2 

×

 3)

7

optical pick-up
(KMS-241B/J1NP)

4

screw
(B2 

×

 3)

4

screw
(P1.7 

×

 1.8)

5

bracket (SL)

9

two screws
(P1.7 

×

 1.8)

!º

retainer (SP)

!¡

SP motor ass’y
(spindle) (M901)

7

screw
(B2 

×

 3)

2

two screws
(2 

×

 8)

3

sensor board

1

Remove solders of motors.
(M901, M902)

8

base (SL)

6

SL motor ass’y
(sled) (M902)

– 18 –

This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and AM (MW) Auto Scan/Stop Level adjustments
can be performed easier than it in ordinary procedure.

<Set the Test Mode>
1. Turn ON the regulated power supply. ( The clock is displayed)

 Press the

[OFF]

button, if the clock is not displayed.

2. Push the preset 

[4]

 button.

3. Push the preset

[5]

button.

4. Press the preset

[1]

button for more than two seconds.

5. Then the display indicates all lights, the test mode is set.

<Release the Test mode>
1. Push the 

[OFF]

 button.

MD section adjustments are done automatically in this set.

3. Adjust the volume RV2 on TU1 by turning clockwise untill

“0” is shown next to “FM” on the display window, If “0” is
already shown or the volume RV2 has been turned too far,
turn it back counterclockwise untill “0” is disappeared once,
then try this adjustment.

Display

See the adjustment location from on page 22 for the ad-
justment.

 0 dB=1 µV

When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.

 Adjust the tuner section in the sequence shown below.

1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment (MDX-C7970)
3. FM Stereo Separation Adjustment (Wide) (MDX-C7970R)
4. FM Stereo Separation Adjustment (Narrow) (MDX-C7970R)
5. FM RDS S-Meter Adjustment (MDX-C7970R)
6. AM (MW) Auto Scan/Stop Level Adjustment

[SOURCE]

 button

: FM

FREQUENCY SELECT switch : FM 200 k (E model)

Procedure:
1. Set to the test mode.
2. Push the 

[SOURCE]

 button and set to FM.

Display

set

antenna jack (CN1)

FM RF signal

generator

Carrier frequency : 97.9 MHz (MDX-C7970)

98.0 MHz (MDX-C7970R)

Output level

: 22 dB (12.6 

µ

V)

Mode

: mono

Modulation

: 1 kHz, 22.5 kHz deviation (30%)

0.01 

µ

F

SHUF

*1

SHUF

*1

*1: MDX-C7970R indicates “98.00”.

Adjustment Location: See page 22.

– 19 –

FM Stereo

Level meter

Level meter

signal generator

connection

reading (dB)

output channel

L-CH

L-CH

A

B

L-CH

R-CH

Adjust RV3 on TU1

for minimum reading.

R-CH

R-CH

C

R-CH

L-CH

D

FM Stereo

Level meter

Level meter

signal generator

connection

reading (dB)

output channel

L-CH

L-CH

A

B

R-CH

L-CH

Adjust RV4 on TU1

for minimum reading.

R-CH

R-CH

C

D

L-CH

R-CH

Adjust RV4 on TU1

for minimum reading.

[SOURCE]

 button

: FM

FREQUENCY SELECT switch : FM 200 k (E model)

FM RF signal

generator

Carrier frequency : 97.9 MHz
Output level

: 70 dB (3.2 mV)

Mode

: stereo

Modulation

: main : 1 kHz, 33.75 kHz deviation (45%)
  sub : 1 kHz, 33.75 kHz deviation (45%)

:

 19 kHz pilot: 7.5 kHz deviation (10%)

0.01 

µ

F

set

antenna jack (J1)

+
–

LINE OUT jack (CNP300)

level meter

10 k

Ω

[SOURCE]

 button : FM

[SHIFT]

 button

: ON (light up SET UP and PLAY MODE)

Preset [4]

(PLAY MODE) 

→

[5]

(

→

) buttons

: WIDE mode

FM RF signal

generator

Carrier frequency : 98.00 MHz
Output level

: 70 dB (3.2 mV)

Mode

: stereo

Modulation

: main : 1 kHz, 33.75 kHz deviation (45%)
  sub : 1 kHz, 33.75 kHz deviation (45%)

:

 19 kHz pilot: 7.5 kHz deviation (10%)

0.01 

µ

F

set

antenna jack (J1)

+
–

level meter

10 k

 

Ω

LINE OUT jack (CNP300)

(75 

Ω)

Procedure:
1. Adjust the volume RV3 on FM/AM tuner unit (TU1) for the

best separation.

L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.

Specification: Separation more than 24 dB

Adjustment Location: See page 22.

L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.

Specification: Separation more than 30 dB

Adjustment Location: See page 22.

– 20 –

FM Stereo

Level meter

Level meter

signal generator

connection

reading (dB)

output channel

L-CH

L-CH

A

B

L-CH

R-CH

Adjust RV4 on TU1

for minimum reading.

R-CH

R-CH

C

R-CH

L-CH

D

[SOURCE]

 button : FM

[SHIFT]

 button

: ON (light up SET UP and PLAY MODE)

Preset [4]

(PLAY MODE) 

→

[5]

(

→

) buttons

: NARROW mode

FM RF signal

generator

Carrier frequency : 98.00MHz
Output level

: 70 dB (3.2 mV)

Mode

: stereo

Modulation

: main : 1 kHz, 20 kHz deviation (26.7%)
  sub : 1 kHz, 20 kHz deviation (26.7%)

:

 19 kHz pilot: 7.5 kHz deviation (10%)

0.01 

µ

F

set

antenna jack (J1)

+
–

level meter

10 k

 

Ω

(75 

Ω)

LINE OUT jack (CNP300)

[SOURCE]

 button : FM

Procedure:
1. Set to the test mode. (See page 18)
2. Push the 

[SOURCE]

 button and set to FM.

Display

set

antenna jack (J1)

FM RF signal

generator

Carrier frequency

: 98.00 MHz

Output level

: 35 dB (56.2 

µ

V)

Mode

: mono

Modulation

: no modulation

0.01 

µ

F

SHUF

SHUF

Procedure:
1. Adjust the volume RV4 on FM/AM tuner unit (TU1) for the

best separation.

3. Push the preset 

[10]

 button .

4. Adjust RV1 on MAIN board so that the display indication is

“13.2”.

Display

Specification: Display indication: 13.0 to 13.4

Adjustment Location: See page 22.

L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.

Specification: Separation more than 18 dB

Adjustment Location: See page 22.