STR-KM22, STR-KM55, STR-KM77 - Sony Audio Service Manual (repair manual)

2015G81-1

© 

2015.07

This receiver incorporates Dolby* Digital and Pro 

Logic Surround and the DTS** Digital Surround 

System.

* 

Manufactured under license from Dolby 

Laboratories. Dolby, Pro Logic, and the double-D 

symbol are trademarks of Dolby Laboratories.

**  Manufactured under license under U.S. Patent Nos: 

5,956,674; 5,974,380; 6,226,616; 6,487,535 & 

other U.S. and worldwide patents issued & pending. 

DTS, the Symbol, & DTS and the Symbol together 

are registered trademarks & DTS Digital Surround | 

96/24 is a trademark of DTS, Inc. Product includes 

software. © DTS, Inc. All Rights Reserved.

This receiver incorporates High-Defi nition Multimedia 

Interface (HDMI

TM

) technology.

The terms HDMI and HDMI High-Defi nition 

Multimedia Interface, and the HDMI Logo are 

trademarks or registered trademarks of HDMI 

Licensing LLC in the United States and other countries.

iPhone and iPod touch are trademarks of Apple Inc., 

registered in the U.S. and other countries.

All other trademarks and registered trademarks are of 

their respective holders. In this manual, ™ and ® marks 

are not specifi ed.

“Made for iPod” and “Made for iPhone” mean that 

an electronic accessory has been designed to connect 

specifi 

cally to iPod or iPhone, respectively, and 

has been certifi ed by the developer to meet Apple 

performance standards.

Apple is not responsible for the operation of this device 

or its compliance with safety and regulatory standards. 

Please note that the use of this accessory with iPod or 

iPhone may affect wireless performance.

Windows Media is either a registered trademark or 

trademark of Microsoft Corporation in the United 

States and/or other countries.

•  STR-KM22 is the receiver section in HT-M22
•  STR-KM55 is the receiver section in HT-M55
•  STR-KM77 is the receiver section in HT-M77

Photo: STR-KM77

– Continued on next page –

This product is protected by certain intellectual property 

rights of Microsoft Corporation. Use or distribution of 

such technology outside of this product is prohibited 

without a license from Microsoft or an authorized 

Microsoft subsidiary.

MPEG Layer-3 audio coding technology and patents 

licensed from Fraunhofer IIS and Thomson.

“x.v.Color (x.v.Colour)” and “x.v.Color (x.v.Colour)” 

logo are trademarks of Sony Corporation.

“BRAVIA” is a trademark of Sony Corporation.

“PlayStation” is a registered trademark of Sony 

Computer Entertainment Inc.

“WALKMAN” and “WALKMAN” logo are registered 
trademarks of Sony Corporation.

MICROVAULT is a trademark of Sony Corporation.

The  Bluetooth

®

 word mark and logos are registered 

trademarks owned by Bluetooth SIG, Inc. and any use 
of such marks by Sony Corporation is under license.
Other trademarks and trade names are those of their 
respective owners.

The N Mark is a trademark or registered trademark 
of NFC Forum, Inc. in the United States and in other 
countries.

Android

TM

 and Google Play are trademarks of Google 

Inc.

Power Output
• STR-KM77
Stereo mode output (rated) (6 ohms, 1 kHz, THD 1%)
 

 

120 W + 120 W

1)

Surround mode output

2)

 (reference) 

(6 ohms, 1 kHz, THD 30%)
 RMS 

output

 

FRONT: 

264 W per channel

1)

 CENTER: 

266 

W

1)

 

SURROUND: 

264 W per channel

1)

 

SURROUND BACK:  264 W per channel

1)

Surround mode output

2)

 (reference) 

(4 ohms, 100 Hz, THD 30%)
 

SUBWOOFER: 

300 W per channel

1)

• STR-KM55
Stereo mode output (rated) (6 ohms, 1 kHz, THD 1%)
 

 

120 W + 120 W

1)

Surround mode output

3)

 (reference) 

(6 ohms, 1 kHz, THD 30%)
 RMS 

output

 

FRONT: 

270 W per channel

1)

 CENTER: 

270 

W

1)

 

SURROUND: 

270 W per channel

1)

Surround mode output

3)

 (reference) 

(4 ohms, 100 Hz, THD 30%)
 

SUBWOOFER: 

300 W per channel

1)

• STR-KM22
Stereo mode output (rated) (6 ohms, 1 kHz, THD 1%)
 

 

100 W + 100 W

1)

Surround mode output

3)

 (reference) 

(6 ohms, 1 kHz, THD 30%)
 RMS 

output

 

FRONT: 

252 W per channel

1)

 CENTER: 

252 

W

1)

 

SURROUND: 

252 W per channel

1)

Surround mode output

3)

 (reference) 

(4 ohms, 100 Hz, THD 30%)
 

SUBWOOFER: 

290 W per channel

1)

Input/Output (HDMI Repeater block)

4096 × 2160p @ 59.94/60 Hz

 a

1)

–

–

–

4096 × 2160p @ 50 Hz

 a

1)

–

–

–

3840 × 2160p @ 59.94/60 Hz

 a

1)

–

–

–

3840 × 2160p @ 50 Hz

 a

1)

–

–

–

4096 × 2160p @ 23.98/24 Hz

 a

2)

–

–

–

3840 × 2160p @ 29.97/30 Hz

 a

2)

–

–

–

3840 × 2160p @ 25 Hz

 a

2)

–

–

–

3840 × 2160p @ 23.98/24 Hz

 a

2)

–

–

–

1920 × 1080p @ 59.94/60 Hz

a

–

a

a

1920 × 1080p @ 50 Hz

a

–

a

a

1920 × 1080p @ 29.97/30 Hz

a

a

a

a

1920 × 1080p @ 25 Hz

a

a

a

a

1920 × 1080p @ 23.98/24 Hz

a

a

a

a

1920 × 1080i @ 59.94/60 Hz

a

a

a

a

1920 × 1080i @ 50 Hz

a

a

a

a

1280 × 720p @ 59.94/60 Hz

a

a

a

a

1280 × 720p @ 50 Hz

a

a

a

a

1280 × 720p @ 29.97/30 Hz

a

a

a

a

1280 × 720p @ 23.98/24 Hz

a

a

a

a

720 × 480p @ 59.94/60 Hz

a

–

–

–

720 × 576p @ 50 Hz

a

–

–

–

640 × 480p @ 59.94/60 Hz

a

–

–

–

1)

 Supports YUV 4:2:0 / 8 bit format only.

2)

 Supports 8 bit format only.

•Abbreviation
 AR   

: 

Argentina 

model

 AUS  

: 

Australian 

model

  E12 

 : 220-240 V AC area in E model

  E51 

 : Chilean and Peruvian models

  EA 

 : Saudi Arabia model

  SAF 

 : South African model

  SP 

 : Singapore model

 TH   

: 

Thai 

model

1)

Measured under the following conditions:

 SAF, E51, SP, E12 

240 V AC, 50 Hz

 EA 

127 V AC, 60 Hz

 AUS, AR, TH 

230 V AC, 50 Hz

2) 

Reference power output for front, center, surround, 
surround back speakers and subwoofers. Depending on 
the sound fi eld settings and the source, there may be no 
sound output.

3) 

Reference power output for front, center, surround 
speakers and subwoofer(s). Depending on the sound 
fi eld settings and the source, there may be no sound 
output.

Inputs
 

Analog 

Sensitivity: 800 mV/

  

50 

kilohms

 

Digital (Coaxial) 

Impedance: 75 ohms

Tone
 

Gain levels 

±6 dB, 1 dB step

Reproduction frequency range
 

28 Hz – 20,000 Hz

Tuning range 

87.5 MHz – 108.0 MHz

Antenna (aerial) 

FM wire antenna (aerial)

Antenna (aerial) terminals  75 ohms, unbalanced

Tuning range

Tuning scale
10 kHz step

9 kHz step

E51, AR

530 kHz – 
1,710 kHz

531 kHz – 
1,710 kHz

EA, SAF, AUS, 
TH, E12, SP

–

531 kHz – 
1,602 kHz

Antenna (aerial) 

Loop antenna (aerial)

(Except for South Africa and Argentina models)
Supported format*
  MP3(MPEG 1 Audio Layer-3): 

32 kbps – 320 kbps, VBR

  WMA: 

 

 

48 kbps – 192 kbps

  AAC:  

 

 

16 kbps – 320 kbps

  WAV:  

 

 

8 kHz – 48 kHz, 16 bit PCM

*Compatibility with all encoding/writing software, recording devices and recording 
  media cannot be guaranteed.

Transfer speed 

 

 

High-speed

Supported USB device   

Mass Storage Class

Maximum current   

 

500 mA

Communication system   

Bluetooth Specifi cation version 3.0

Output  

  Bluetooth Specifi cation Power Class 2

Maximum communication range 

Line of sight approx. 10 m

1)

Frequency band 

 

 

2.4 GHz band (2.4000 GHz – 2.4835 GHz)

Modulation method 

 

FHSS (Freq Hopping Spread Spectrum)

Compatible Bluetooth profi les

2)

 

A2DP (Advanced Audio Distribution Profi le)

   

 

 

AVRCP 1.3 (Audio Video Remote Control 

  

 

 

Profi le)

Supported Codecs

3)

  

SBC

4)

, AAC

Transmission range (A2DP) 

20 Hz – 20,000 Hz 

   

 

 

(Sampling frequency 44.1 kHz)

1) 

The actual range will vary depending on factors such as obstacles between devices, 
magnetic fi elds around a microwave oven, static electricity, cordless phone, reception 
sensitivity, antenna’s performance, operating system, software application, etc.

2) 

Bluetooth standard profi les indicate the purpose of Bluetooth communication 
between devices.

3) 

Codec: Audio signal compression and conversion format

4) 

Subband Codec

Power requirements

SAF, TH, SP

230 V AC – 240 V AC, 50/60 Hz

E51

120/220/240 V AC, 50/60 Hz

AR

220 V AC – 230 V AC, 50/60 Hz

EA

120 V AC – 127/220/230 V AC – 240 V AC,50/60 Hz

AUS

230 V AC, 50 Hz

E12

220 V AC – 240 V AC, 50/60 Hz

Power consumption 

195 W (STR-KM77)

  

 

185 

W 

(STR-KM55)

  

 

150 

W 

(STR-KM22)

Power consumption (during standby mode)
   

 

0.3 W (When “CTRL HDMI” is set to “CTRL OFF”)

Dimensions (width/height/depth) (Approx.)
   

 

430 mm × 178 mm × 336 mm

   

 

including projecting parts and controls

Mass (Approx.) 

 

10.3 kg (STR-KM77/STR-KM55)

   

 

8.5 kg (STR-KM22)

Design and specifi cations are subject to change without notice.

0 OR  DOTTED  LINE  

0 ON  THE  SCHEMATIC  DIAGRAMS  AND  IN  

 ................................................. 4

2-1.   Disassembly Flow .............................................................. 6
2-2.   Case .................................................................................... 6
2-3.   Front Panel Section ............................................................ 7
2-4.   Back Panel Section ............................................................ 8
2-5.   SUB RECTIFIER Board, Main Block ............................... 9
2-6.   DSP Board, SURR BACK AMP Board, MAIN Board,

Heatsink Block ................................................................. 10

 ...............................................................11

 ........................................... 13

5-1.  Block Diagram - HDMI/USB Section - ........................... 15
5-2.  Block Diagram - AUDIO Section - .................................. 16
5-3.  Block Diagram - AMP Section - ...................................... 17
5-4. Block 

Diagram 

- DISPLAY/POWER SUPPLY Section - ......................... 18

5-5. Printed 

Wiring 

Board 

- MAIN Board (Component side) - .................................. 21

5-6. Printed 

Wiring 

Board 

- MAIN Board (Conductor side) - ................................... 22

5-7.  Schematic Diagram - MAIN Board (1/9) - ...................... 23
5-8.  Schematic Diagram - MAIN Board (2/9) - ...................... 24
5-9.  Schematic Diagram - MAIN Board (3/9) - ...................... 25
5-10.  Schematic Diagram - MAIN Board (4/9) - ...................... 26
5-11.  Schematic Diagram - MAIN Board (5/9) - ...................... 27
5-12.  Schematic Diagram - MAIN Board (6/9) - ...................... 28
5-13.  Schematic Diagram - MAIN Board (7/9) -. ..................... 29
5-14.  Schematic Diagram - MAIN Board (8/9) - ...................... 30
5-15.  Schematic Diagram - MAIN Board (9/9) - ...................... 31
5-16.  Printed Wiring Board - HDMI RE PC Board - ................ 32
5-17.  Schematic Diagram - HDMI RE PC Board (1/2) - .......... 33
5-18.  Schematic Diagram - HDMI RE PC Board (2/2) - .......... 34

5-19.  Printed Wiring Board - DSP Board - ............................... 35
5-20.  Schematic Diagram - DSP Board (1/2) - ......................... 36
5-21.  Schematic Diagram - DSP Board (2/2) - ......................... 37
5-22.  Printed Wiring Board - STANDBY Board - .................... 38
5-23.  Schematic Diagram - STANDBY Board - ....................... 39
5-24. Printed Wiring Board 

- SUB RECTIFIER Board (KM55, KM77) - .................. 40

5-25. Schematic Diagram 

- SUB RECTIFIER Board (KM55, KM77) - .................. 40

5-26.  Printed Wiring Board - TUNER1AMPR Board - ............ 41
5-27.  Schematic Diagram - TUNER1AMPR Board - ............... 41
5-28. Printed Wiring Board 

- FRONT USB Board (EXCEPT SAF, AR) - .................. 41

5-29. Schematic Diagram 

- FRONT USB Board (EXCEPT SAF, AR) - .................. 41

5-30.  Printed Wiring Board 

- SURR BACK AMP Board (KM77) - ............................ 42

5-31. Schematic Diagram 

- SURR BACK AMP Board (KM77) - ............................ 42

5-32.  Printed Wiring Board - DISPLAY Board - ...................... 43
5-33.  Schematic Diagram - DISPLAY Board - ......................... 43
5-34.  Printed Wiring Board - LED BAR Board - ...................... 44
5-35.  Schematic Diagram - LED BAR Board - ........................ 45
5-36.  Printed Wiring Board - NFC CHAIN Board - ................. 46
5-37.  Schematic Diagram - NFC CHAIN Board - .................... 46
5-38.  Printed Wiring Board - POWER KEY Board -................ 46
5-39.  Schematic Diagram - POWER KEY Board - .................. 46

6-1. Case 

Section 

..................................................................... 63

6-2.  Front Panel Section .......................................................... 64
6-3.  Back Panel Section .......................................................... 65
6-4. Chassis 

Section 

................................................................ 66

6-5. Heatsink 

Section 

.............................................................. 67

 ................................ 68

Notes on chip component replacement
• 

Never reuse a disconnected chip component.

• 

Notice that the minus side of a tantalum capacitor may be da-

 

maged by heat.

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!

•   Strong viscosity
 

Unleaded solder is more viscou-s (sticky, less prone to fl ow) 
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.

Special Component Notice
The components identifi ed by mark 

9 contain confi dential

information.
Strictly follow the instructions whenever the components are
repaired and/or replaced.

NOTE  OF  REPLACING  THE  IC2010,  IC2700  AND 
IC2903  ON  THE  MAIN BOARD
IC2010, IC2700 and IC2903 on the MAIN board cannot exchange 
with single. When these parts on the MAIN board are damaged, 
exchange the entire mounted board.

NOTE  OF  REPLACING  THE  IC3009  ON  THE  HDMI 
RE PC BOARD
IC3009 on the HDMI RE PC board cannot exchange with single. 
When these parts on the HDMI RE PC board are damaged, ex-
change the entire mounted board.

NOTE  OF  REPLACING  THE  IC5001  ON  THE  DSP  
BOARD
IC5001 on the DSP board cannot exchange with single. When 
these parts on the DSP board are damaged, exchange the entire 
mounted board.

KM77: SAF

4-485-866-0[]

KM77: SP

4-485-866-2[]

KM77: AUS

4-485-866-3[]

KM77: E51

4-485-866-5[]

KM77: AR

4-485-866-7[]

KM55: E12

4-489-706-1[]

KM55: SAF

4-489-706-2[]

KM55: EA

4-489-706-3[]

KM55: E51

4-489-706-5[]

KM55: AR

4-489-706-7[]

KM55: TH

4-489-706-9[]

KM22: SAF

4-489-707-0[]

KM22: EA

4-489-707-1[]

KM22: SP

4-489-707-2[]

KM22: TH

4-489-707-4[]

KM22: E51

4-489-707-5[]

KM22: AR

4-489-707-8[]

• Abbreviation
 AR   

: 

Argentina 

model

 AUS  

: 

Australian 

model

  E12 

 : 220-240 V AC area in E model

  E51 

 : Chilean and Peruvian models

  EA 

 : Saudi Arabia model

  SAF 

 : South African model

  SP 

 : Singapore model

 TH   

: 

Thai 

model