NW-E55, NW-E75, NW-E90, NW-E95 - Sony Audio Service Manual (repair manual). Page 2

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Flexible Circuit Board Repairing
• Keep the temperature of the 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.

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

aged by heat.

z

Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)

Unleaded solder has the following characteristics.
• Unleaded solder melts at a temperature about 40

°C higher than

ordinary solder.

Ordinary soldering irons can be used but the iron tip has to be

applied to the solder joint for a slightly longer time.

Soldering irons using a temperature regulator should be set to

about 350

°C.

Caution: The printed pattern (copper foil) may peel away if

the heated tip is applied for too long, so be careful!

• Strong viscosity

Unleaded solder is more viscous (sticky, less prone to flow)

than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.

• Usable with ordinary solder

It is best to use only unleaded solder but unleaded solder may

also be added to ordinary solder.

•  IC400 (microcomputer) and IC450 (nor flash sram) on MAIN
   board cannot be replaced individually.
   Replace it with MAIN board assembly for service.

Microsoft, Windows and Windows Media are trademarks or
registered trademarks of Microsoft Corporation in the United States
and/or other countries.
US and foreign patents licensed from Dolby Laboratories.
All other trademarks and registered trademarks are trademarks or
registered trademarks of their respective holders.

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3-1. Case, Chassis (Front) Assy ··········································· 6
3-2. DISPLAY Board Assy ·················································· 7
3-3. MAIN Board Assy ························································ 7

4-1. Block Diagram ······························································ 9
4-2. Printed Wiring Board

– DISPLAY Board (Side A) – ····································· 10

4-3. Printed Wiring Board

– DISPLAY Board (Side B) – ····································· 11

4-4. Schematic Diagram – DISPLAY Board – ·················· 12
4-5. Printed Wiring Board – MAIN Board (Side A) – ······· 13
4-6. Printed Wiring Board – MAIN Board (Side B) – ······· 14
4-7. Schematic Diagram – MAIN Board (1/2) – ··············· 15
4-8. Schematic Diagram – MAIN Board (2/2) – ··············· 16

5-1. Overall Assy Section ··················································· 18
5-2. MAIN Board Section ·················································· 19

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