DOWNLOAD Sony KV-27HS420 (serv.man2) Service Manual ↓ Size: 14.46 MB | Pages: 127 in PDF or view online for FREE

+B overcurrent (OCP) 
Occurs when excessive current fl ows through R5013. The increase in voltage across R5013 causes the output of Q5004 to go high, and this high 
signal goes to the micro. 

+B overvoltage (OVP) 
IC6505 detects +B OVP condition and turns on Q6522. This sends a high signal to the micro and also shuts down the AC relay.

V-STOP 
Occurs when an absence of the vertical defl ection pulse is detected by pin 24 of IC2801 (B Board). Power supply will shut down when waveform 
interval exceeds 2 seconds. 

White Balance Failure
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC2801. TV will stay on, but there will be 
no picture.

*(Refers to the RGB levels of the AKB detection Ref pulse that detects IK).

Low B OCP/OVP
Occurs when set 5V is out.

Horizontal Defl ection Stopped
Occurs when either: 
 

1) a +B overcurrent is detected (IC5007), or 

 

2) overheating is detected (Thermistor TH5002).

 

CAUTION! - Heat sink on IC5004 is -15V.  Do not to allow 
heat sink to touch GND or any other components.

 

Heat sink on Q8018 VpK=250V. Do not touch or short to 
GND or other components.

 

CAUTION! - Pay attention to Neck Assembly WY Board wire 
harness to B Board. The WY Board can easily break if there 
is sudden or excessive tension on the harness.

1

  Lift lever up on the right and left sides of the chassis bracket 

and gently pull the chassis assembly away from the bezel.

2

  Pull up and rotate both the A and D Boards in order to 

service the unit. 

1

  Lift lever up on the right and left sides of the chassis 

bracket and gently pull the chassis assembly away from 
the bezel.

Rear Cover

5 Screws
 +BVTP 4 x 16
TYPE2 TT (B) 

5 Screws
 +BVTP 4 x 16
TYPE2 TT (B) 

4 Screws
 +BVTP 4 x 16
TYPE2 TT (B) 

1.  Discharge the anode of the CRT and remove the 

 anode 

cap.

2.  Unplug all interconnecting leads from the defl ection

 

yoke, neck assembly, degaussing coils and CRT 

 grounding 

strap.

3.  Remove the CH Board from the CRT.

4.  Remove the chassis assembly.

5.  Loosen the neck assembly fi xing screw and remove.

6.  Loosen the defl ection yoke fi xing screw and remove.

7.  Place the set with the CRT face down on a cushion 

 

and remove the degaussing coil holders.

8.  Remove the degaussing coils.

9.  Remove the CRT grounding strap and spring 

 tension 

devices.

10. Unscrew the four CRT fi xing screws [located on 

 

each CRT corner] and remove the CRT 

 

[Take care not to handle the CRT by the neck].

WARNING: High voltage remains in the CRT even after the power is disconnected. To avoid electric shock, discharge CRT before attempting to 
remove the anode cap. After removing the anode cap, short circuit to either the metal chassis, CRT shield, or carbon painted on the CRT. 

NOTE: After removing the anode cap, short circuit the anode of the picture tube and the anode cap to either the metal chassis, CRT shield or carbon 
painted on the CRT.

Turn up one side of the rubber cap in 
the direction indicated by arrow a .

Use your thumb to pull the rubber 
cap fi rmly in the direction indicated 
by arrow b .

When one side of the rubber cap separates from 
the anode button, the anode cap can be removed 
by turning the rubber cap and pulling it in the 
direction of arrow c .

1.  Do not use sharp objects which may cause damage to the surface of the anode 

cap. 

2.  To avoid damaging the anode cap, do not squeeze the rubber covering too 

hard. A material fi tting called a shatter-hook terminal is built into the rubber. 

3.  Do not force turn the foot of the rubber cover. This may cause the shatter-hook 

terminal to protrude and damage the rubber.

Coated

Earth

Ground

Strap

4

3

4

6

5

2

9

3

8

10

7

1

[CH]

or

[CX]

[WY]

[CH]

or

[CX]