ST-SDB900 - Sony Audio Service Manual (repair manual). Page 2

2

Unleaded solder
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!

...................................................................

3

...............................................................

4

3-1.

Block Diagram ................................................................

9

3-2.

Printed Wiring Board – MAIN Board (Side A) – ............ 10

3-3.

Printed Wiring Board – MAIN Board (Side B) – ............ 11

3-4.

Schematic Diagram – MAIN Board (1/3) – .................... 12

3-5.

Schematic Diagram – MAIN Board (2/3) – .................... 13

3-6.

Schematic Diagram – MAIN Board (3/3) – .................... 14

3-7.

Printed Wiring Board
– TRANS, AC SW, JOG, RM Board – ............................ 15

3-8.

Printed Wiring Board – DISPLAY Board – .................... 16

3-9.

Schematic Diagram – DISPLAY Board – ....................... 17

4-1.

Case, Front Panel Section ................................................ 20

4-2.

Chassis Section ................................................................ 21

.................................. 22

COMPONENTS IDENTIFIED BY MARK 0  OR DOTTED LINE
WITH MARK 0 ON THE SCHEMATIC DIAGRAMS AND IN THE
PARTS LIST ARE CRITICAL TO SAFE OPERATION. REPLACE
THESE COMPONENTS WITH SONY PARTS WHOSE PART NUM-
BERS APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLE-
MENTS PUBLISHED BY SONY.

• 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.

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.

174.928MHz

5A

209.936MHz

10A

176.640MHz

5B

211.648MHz

10B

178.352MHz

5C

213.360MHz

10C

180.064MHz

5D

215.072MHz

10D

181.936MHz

6A

216.928MHz

11A

183.648MHz

6B

218.640MHz

11B

185.360MHz

6C

220.352MHz

11C

187.072MHz

6D

222.064MHz

11D

188.928MHz

7A

223.936MHz

12A

190.640MHz

7B

225.648MHz

12B

192.352MHz

7C

227.360MHz

12C

194.064MHz

7D

229.072MHz

12D

195.936MHz

8A

230.784MHz

13A

197.648MHz

8B

232.496MHz

13B

199.360MHz

8C

234.208MHz

13C

201.072MHz

8D

235.776MHz

13D

202.928MHz

9A

237.488MHz

13E

204.640MHz

9B

239.200MHz

13F

206.352MHz

9C

208.064MHz

9D

* This tuner does not support L-Band reception.

Since this connector tends to break, be careful of handling.
When exchanging DAB TUNER MODULE and hard to remove 
a cable, please also exchange cables together.

DAB TUNER MODULE

Cable

Main board