STR-K675P - Sony Audio Service Manual (repair manual)

US Model

2005C1678-1
© 2005.03

• STR-K675P is the tuner and the amplifier

section in HT-DDW675.

Manufactured under license from Dolby Laboratories.
“Dolby”, “Pro Logic” and the double-D symbol are trademarks
of Dolby Laboratories.
“DTS” and “DTS Digital Surround” are registered trademarks of
Digital Theater Systems, Inc.

With 6 ohm loads, both channels driven, from 
120 – 20,000 Hz; rated 70 watts per channel 
minimum RMS power, with no more than 0.7% 
total harmonic distortion from 250 milliwatts to 
rated output.

Power Output

1)

(6 ohms 1 kHz, THD 10%) 
FRONT

2)

: 

110 W/ch

CENTER

2)

: 

110 W 

SURR

2)

: 110 

W/ch

Tuning range

87.5 - 108.0 MHz

Antenna

FM wire antenna

Antenna terminals

75 ohms, unbalanced

Intermediate frequency

10.7 MHz

Tuning range
With 10-kHz tuning scale:  530 - 1,710 kHz

3)

With 9-kHz tuning scale:  531 - 1,710 kHz

3)

Antenna

Loop antenna

Intermediate frequency

450 kHz

3) You can change the AM tuning scale to 9 kHz or 

10 kHz. After tuning in any AM station, turn off the 
receiver. While holding down PRESET TUNING + 
or TUNING +, press ?/1. All preset stations will be 
erased when you change the tuning scale. To reset 
the scale to 10 kHz (or 9 kHz), repeat the procedure.

1) Measured under the following conditions:

2) Depending on the sound field settings and the 

source, there may be no sound output.

Inputs (Analog)

Inputs (Digital)

Output (Analog)

Reproduction frequency range:

28 – 20,000 Hz

Tone

120 V AC, 60 Hz

SA-CD/CD, DVD
VIDEO 1, 2

Sensitivity: 800 mV
Impedance: 50 k ohms

DVD (Coaxial)

Sensitivity: –
Impedance: 75 ohms

 SA-CD/CD (Optical)

Sensitivity: –
Impedance: –

SUB WOOFER

Voltage: 2 V
Impedance: 1 k  ohm

Gain levels

±6 dB, 1 dB step

Power requirements

120 V AC, 60 Hz

Power consumption

Power consumption (during standby mode)

0.2 W

Dimensions (w/h/d) (Approx.)

430 

× 145 × 301.5 mm

(17 

× 5 6/8 × 11 7/8 inches)

including projecting parts 
and controls

Mass (Approx.)

6.5 kg (14 lb 6 oz)

170 W

Design and specifications are subject to change 
without notice

2

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

3

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

7

3-1.

Block Diagram — MAIN Section — .............................. 10

3-2.

Block Diagram — DISPLAY/POWER Section — ........ 11

3-3.

Printed Wiring Board
— DIGITAL Board (Side A) — ...................................... 12

3-4.

Printed Wiring Board
— DIGITAL Board (Side B) — ...................................... 13

3-5.

Schematic Diagram — DIGITAL Board (1/4) — .......... 14

3-6.

Schematic Diagram — DIGITAL Board (2/4) — .......... 15

3-7.

Schematic Diagram — DIGITAL Board (3/4) — .......... 16

3-8.

Schematic Diagram — DIGITAL Board (4/4) — .......... 17

3-9.

Printed Wiring Board — MAIN Section — ................... 18

3-10. Schematic Diagram — MAIN Section (1/3) — ............. 19
3-11. Schematic Diagram — MAIN Section (2/3) — ............. 20
3-12. Schematic Diagram — MAIN Section (3/3) — ............. 21
3-13. Printed Wiring Board — STANDBY Section — ........... 22
3-14. Printed Wiring Board — DISPLAY Section — ............. 23
3-15. Schematic Diagram — DISPLAY Section — ................ 24
3-16. Printed Wiring Board — VIDEO Board — .................... 25
3-17. Schematic Diagram — VIDEO Board — ...................... 26

4-1.

Front Panel Section ......................................................... 34

4-2.

Chassis Section ................................................................ 35

.................................. 36

After correcting the original service problem, perform the following
safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage.
Check leakage as described below.

The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microamperes.).
Leakage current can be measured by any one of three methods.

1. A commercial leakage tester, such as the Simpson 229 or RCA

WT-540A. Follow the manufacturers’ instructions to use these
instruments.

2. A battery-operated AC milliammeter. The Data Precision 245

digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a

VOM or battery-operated AC voltmeter. The “limit” indication
is 0.75 V, so analog meters must have an accurate low-voltage
scale. The Simpson 250 and Sanwa SH-63Trd are examples
of a passive VOM that is suitable. Nearly all battery operated
digital multimeters that have a 2 V AC range are suitable.  (See
Fig. A)

1.5 k

Ω

0.15 

µ

F

AC
voltmeter
(0.75 V)

To Exposed Metal
Parts on Set

Earth Ground

• Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

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 viscou-s (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.

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