HS-JM450 - Sony Audio Service Manual (repair manual)

E Model

2005H02-1

© 2005.08

Model Name Using Similar Mechanism

WM-GX221

Tape Transport Mechanism Type

MT-WMGX221-175

FM: 87.6-107.9 MHz
AM: 531-1 602 kHz

Playback: 40 - 15 000 Hz
Recording: 100 - 8 000 Hz
(when setting REC/PLAY to NORM)

Microphone (MIC) jack

Stereo earphones (i) jack
Load impedance: 8 - 300 

Ω

3 V DC batteries R6 (size AA)
x 2
External DC 3V power sources

 Approx. 112.0 x 82.5 x 39.0 mm
(4 

1

/

2

 x 3 

1

/

4

 x 1 

9

/

16

 inches),

excl. projecting parts and controls

Approx. 220 g (7.8 oz) (main unit only)

Stereo earphones (1)

Battery life (Approx. hours) (JEITA*)

Sony alkaline

Sony R6P(SR)

LR6(SG)**

(using stereo earphones)
Playback

24

7

Radio

48

15

Mic recording

20

4.5

Radio recording

12

3

(using the speakers)
Playback

15

4.5

Radio

26

6

Radio recording

11.5

3

* Measured by the standard of JEITA (Japan Electronics and Information

Technology Industries Association) (using a Sony HF series cassette

tape)

** When using Sony LR6(SG) “STAMINA” alkaline dry batteries

(produced in Japan)

Note
The battery life may be shorter depending on the operating condition, the
surrounding temperature and battery type.

Design and specifications are subject to change without notice.

2

Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

Flexible Circuit Board Repairing
• Keep the temperature of soldering iron around 270˚C

during repairing.

• Do not touch the soldering iron on the same conductor of the

circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

or unsoldering.

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3-1. Cabinet (Front) Assy ······································································· 5
3-2. MAIN Board, Mechanism Deck (MT-WMGX221-175) ················ 6
3-3. Belts, M601, HRP901, HE901 ························································ 7
3-4. SUB Board ······················································································ 7

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······················································································ 10

6-1. Block Diagram – Tuner Section – ················································· 11
6-2. Block Diagram – Main Section – ················································· 12
6-3. Printed Wiring Boards (Side A) ···················································· 13
6-4. Printed Wiring Boards (Side B) ···················································· 14
6-5. Schematic Diagram – MAIN Board (1/2) – ·································· 15
6-6. Schematic Diagram – MAIN Board (2/2) – ·································· 16
6-7. IC Block Diagrams ······································································· 17

······································································ 19

7-1. Overall Section ············································································· 19
7-2. Cabinet (Front) Section ································································· 20
7-3. Mechanism Deck Block-1 (MT-WMGX221-175) ······················· 21
7-4. Mechanism Deck Block-2 (MT-WMGX221-175) ······················· 22

······················································· 23

3

In this set, record/play mode is detected using the switch S704 (TAPE POWER).
S704 is mounted on the MAIN board. If MAIN board is removed, it becomes impossible to detect
record/play mode.
Where MAIN board is removed, when you measure operation and voltage of each part of the mechanism
deck, please turn on S704.

– MAIN BOARD (SIDE A) —

S704

4

This section is extracted
from instruction manual.

• LOCATION OF CONTROLS

PAUSE .

z 

SPEAKER/i

i

x 

N 

m 

M