DOWNLOAD Sony MHC-EX66 / TC-EX66 / TC-EX660 Service Manual ↓ Size: 711.75 KB | Pages: 26 in PDF or view online for FREE

– 9 –

7

capstan motor

5

Hang the belt.

6

three motor
screws.

4

Remove the solder
of motor lead wire.

1

step screw

3

control board

2

two claws

2

two claws

– 10 –

1. The adjustment should be performed in the publication.

(Be sure to male playback adjustment at first.)

2. The adjustments and measurement should be performed for

both L-CH and R-CH.

•

Switch position
DOLBY NR switch

: OFF

DIRECTION switch

: 

A

•

Standard record position
Deliver the standard input signal level to input jack and set
the REC LEVEL (RV301) control to obtain the standard
output signal level as follows.

set

AF OSC

attenuator

600 

Ω

10 k 

Ω

LINE IN

+
–

LINE OUT

47 k 

Ω

level meter

CQ-102C

30-65 g•cm

FWD

(0.42-0.90 oz•inch)

FWD

1.5-6 g•cm

Back tension

(0.021-0.083 oz•inch)

CQ-102RC

30-65 g•cm

REV

(0.42-0.90 oz•inch)

REV

1.5-6 g•cm

Back tension

(0.021-0.083 oz•inch)

70-130 g•cm

FF, REW

CQ-201B

(0.98-1.80 oz•inch)

1. Clean the following parts with a denatured-alcohol-moistened

swab:

record/playback/earth head pinch roller
rubber belts

capstan

idlers

2. Demagnetize the record/playback head with a head demagne-

tizer. (Do not bring the head demagnetizer close to the erase
head.)

3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the

parts adjusted.

5. The adjustments should be performed with the rated power sup-

ply voltage unless otherwise noted.

source impedance

10 k

Ω

input signal level

0.5 V (– 3.8 dB)

load impedance

47 k

Ω

output signal level

0.5 V (– 3.8 dB)

P-4-A100

10 kHz, – 10 dB

Azimuth Adjustment

P-4-L300

315 Hz,

0 dB

PB Level Adjustment

WS-48B

3 kHz,

0 dB

Tape Speed Adjustment

With the POWER turned OFF, short the test point CN801 (2P) on
the MAIN board (making IC801 pin &¢ “L”) and turn the POWER
ON. Thus, the TEST mode will be activated.
If a recording is done in the TEST mode, the REC MEMORY
mode becomes active where the tape is rewound by the amount of
recording when a rewinding is executed after recording.
After adjustment, make the CN801 (2P) open to release the TEST
mode.

– 11 –

Procedure:
1. Mode: REV playback

2. Turn the adjustment screw for the maximum output levels. If

these levels do not match, turn the adjustment screw until both
of output levels match together within 1 dB.

+
–

set

LINE OUT

frequency counter

test tape
WS-48B
(3 kHz, 0 dB)

47 k 

Ω

1. Set to FWD playback mode.
2. Adjust Variable resistor on the motor (M902) so that the fre-

quency counter reading becomes

3,000 ± 90 Hz.

3. Confirm that the deviation between tape top and tape end is

within 3%.

Adjustment Location: CAPSTAN/REEL motor (M902)

Screw
position

L-CH
peak

within
1dB

output
level

L-CH peak

R-CH peak

within
1dB

angle

R-CH
peak

3. Phase Check

Mode: REV playback

+
–

V

H

+

–

Screen pattern

Good

Wrong

in phase 45

°

90

°

135

°

180

°

LINE OUT

set

R-CH

L-CH

47 k 

Ω

47 k 

Ω

oscilloscope

test tape
P-4-A100
(10 kHz, –10 dB)

4. Set in the FWD mode and repeat the step 1 to 3.
5. After the adjustment, lock the screw with locking compound.

Adjustment Location: Record/Playback head































FWD side

REV side

Adjustment screw

+
–

set

47 k 

Ω

LINE OUT

level meter

test tape
P-4-A100
(10 kHz, – 10 dB)

Procedure:
Mode: FWD playback

M902

adjustable resistor

– 12 –

Setting:
REC LEVEL control: Standard record position (See page 10)
set to the TEST mode (REC MEMRY mode) (See page 10)

Procedure:
1. Mode :Record

+
–

set

LINE OUT

47 k 

Ω

test tape
P-4-L300
(315 Hz, 0 dB)

level meter

Adjust RV151 (L-CH) and RV251 (R-CH) so that the reading on
level meter meets the adjustment limits below.

LINE OUT level: – 7.7 ± 0.5 dB (0.301 to 0.338 V)
Level difference between channels: within 2 dB

Check that the LINE OUT level does not change even if Playback
and Stop operation is repeated several times.

Adjustment Location: MAIN board (See page 13)

Procedure:
Mode: FWD playback

Setting:
REC LEVEL control: Standard record position (See page 10)
Set to the TEST mode (REC MEMRY mode) (See page 10)
Procedure:
1. Mode: Record

set

AF OSC

attenuator

600 

Ω

10 k 

Ω

blank tape
CS-123

LINE IN
1) 315 Hz
2) 10 kHz

50 mV (– 23.8 dB)

2. Mode: Playback

+
–

set

LINE OUT

47 k 

Ω

recorded portion

level meter

3. Confirm playback the signal recorded in step 1 become ad-

justment level as follows.

4. If these levels do not adjustment level, adjust the RV152 (L-

CH) and RV252 (R-CH) to repeat step 1 and 2.

Playback output of 10 kHz to playback
output of 315 Hz: ± 0.5 dB.

Adjustment Location: MAIN board (See page 13)

set

AF OSC

attenuator

600 

Ω

10 k 

Ω

blank tape
CS-123

LINE IN
315 Hz, 50 mV (– 23.8 dB)

2. Mode: Playback

+
–

set

LINE OUT

47 k 

Ω

recorded portion

level meter

3. Confirm playback the signal recorded in step 1 become ad-

justment level as follows.

4. If these levels do not adjustment level, adjust RV153 (L-CH)

and RV253 (R-CH) to repeat step 1 and 2.

– 23.8 ± 0.5 dB (47 to 53 mV)

Adjustment Location: MAIN board (See page 13)