Sony KF-42WE620 / KF-50WE620 Service Manual ▷ View online
6
KF-42WE620/50WE620
KF-42WE620/50WE620
SAFETY CHECK-OUT
After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:
safety checks before releasing the set to the customer:
1. Check the area of your repair for unsoldered or poorly soldered
connections. Check the entire board surface for solder splashes and
bridges.
bridges.
2. Check the interboard wiring to ensure that no wires are “pinched” or
touching high-wattage resistors.
3. Check that all control knobs, shields, covers, ground straps, and
mounting hardware have been replaced. Be absolutely certain that
you have replaced all the insulators.
you have replaced all the insulators.
4. Look for unauthorized replacement parts, particularly transistors,
that were installed during a previous repair. Point them out to the
customer and recommend their replacement.
customer and recommend their replacement.
5. Look for parts which, though functioning, show obvious signs of
deterioration. Point them out to the customer and recommend their
replacement.
replacement.
6. Check the line cords for cracks and abrasion. Recommend the
replacement of any such line cord to the customer.
7. Check the B+ and HV to see if they are specifi ed values. Make sure
your instruments are accurate; be suspicious of your HV meter if sets
always have low HV.
always have low HV.
8. Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage. Check leakage as
described below.
described below.
Leakage Test
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.
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
instructions.
instructions.
2. A battery-operated AC milliampmeter. 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’s 250 and Sanwa SH-63TRD are examples of
passive VOMs that are suitable. Nearly all battery-operated digital
multimeters that have a 2 VAC range are suitable (see Figure A).
V, so analog meters must have an accurate low voltage scale.
The Simpson’s 250 and Sanwa SH-63TRD are examples of
passive VOMs that are suitable. Nearly all battery-operated digital
multimeters that have a 2 VAC range are suitable (see Figure A).
How to Find a Good Earth Ground
A cold-water pipe is a guaranteed earth ground; the cover-plate
retaining screw on most AC outlet boxes is also at earth ground. If the
retaining screw is to be used as your earth ground, verify that it is at
ground by measuring the resistance between it and a cold-water pipe
with an ohmmeter. The reading should be zero ohms.
A cold-water pipe is a guaranteed earth ground; the cover-plate
retaining screw on most AC outlet boxes is also at earth ground. If the
retaining screw is to be used as your earth ground, verify that it is at
ground by measuring the resistance between it and a cold-water pipe
with an ohmmeter. The reading should be zero ohms.
If a cold-water pipe is not accessible, connect a 60- to 100-watt
trouble- light (not a neon lamp) between the hot side of the receptacle
and the retaining screw. Try both slots, if necessary, to locate the hot
side on the line; the lamp should light at normal brilliance if the screw
is at ground potential (see Figure B).
trouble- light (not a neon lamp) between the hot side of the receptacle
and the retaining screw. Try both slots, if necessary, to locate the hot
side on the line; the lamp should light at normal brilliance if the screw
is at ground potential (see Figure B).
To Exposed Metal
Parts on Set
Parts on Set
0.15 F
Earth Ground
AC
Voltmeter
(0.75V)
Voltmeter
(0.75V)
Trouble Light
AC Outlet Box
Ohmmeter
Cold-water Pipe
Figure A. Using an AC voltmeter to check AC leakage.
Figure B. Checking for earth ground.
7
KF-42WE620/50WE620
KF-42WE620/50WE620
SELF-DIAGNOSTIC FUNCTION
Self Diagnosis
Supported model
The units in this manual contain a self-diagnostic function. If an error occurs, the POWER/STANDBY will automatically begin to fl ash. The number of
times the LED fl ashes translates to a probable source of the problem. A defi nition of the POWER/STANDBY fl ash indicators is listed in the instruction
manual for the user’s knowledge and reference. If an error symptom cannot be reproduced, the Remote Commander can be used to review the failure
occurrence data stored in memory to reveal past problems and how often these problems occur.
times the LED fl ashes translates to a probable source of the problem. A defi nition of the POWER/STANDBY fl ash indicators is listed in the instruction
manual for the user’s knowledge and reference. If an error symptom cannot be reproduced, the Remote Commander can be used to review the failure
occurrence data stored in memory to reveal past problems and how often these problems occur.
Diagnostic Test Indicators
When an error occurs, the POWER/STANDBY will fl ash a set number of times to indicate the possible cause of the problem. If there is more than one
error, the LED will identify the fi rst of the problem areas.
Results for all of the following diagnostic items are displayed on screen. No error has occurred if the screen displays a “0”.
When an error occurs, the POWER/STANDBY will fl ash a set number of times to indicate the possible cause of the problem. If there is more than one
error, the LED will identify the fi rst of the problem areas.
Results for all of the following diagnostic items are displayed on screen. No error has occurred if the screen displays a “0”.
Diagnostic Item
Description
No. of times
POWER/STANDBY
lamp flashes
Probable Cause Location
Detected Symptoms
Power does not turn on
0
• Power cord is not plugged in.
• Fuse is burned out.
• Fuse is burned out.
(F1901 on F Board)
• Power does not come
on.
• No power is supplied
to the unit.
• AC power supply is
faulty.
Lamp cover error
3 times
• Lamp cover is not attached
securely.
• No picture/No sound
Fan stopped
4 times
• Fan1, Fan2, or Fan 3 power
is not supplied. .
(A Board)
(A Board)
• Fan connector is not attached
securely
• No picture/No sound
Temp error
4 times
• Temperature is high.
• IIC-E line connector
• IIC-E line connector
(CN8023 on A Board,
CN44 on H Board) is not
attached securely.
CN44 on H Board) is not
attached securely.
• No picture/No sound
Lamp driver error
5 times
• Lamp driver is faulty.
• No picture/No sound
+B OVP error
6 times
• +17V is not supplied.
(G1 Board)
• No picture/No sound
Audio error
7 times
• Audio line is shorted.
(A, G1 Board)
• IC8504 (A Board) or IC4704
(AU Board) is faulty.
• PS1601 or 1602 is opened.
(G1 Board)
• No picture/No sound
D-OVP error
8 times
• +3.3V or +2.5V or 1.8V is
over voltage.
(G3 Board)
(G3 Board)
• No picture/No sound
Lamp error
LAMP-LED flashes
• Lamp for the light source has
burnt out.
• No picture/No sound
8
KF-42WE620/50WE620
KF-42WE620/50WE620
*If a +B overcurrent is detected, stoppage of the vertical defl ection is detected simultaneously. The symptom that is diagnosed fi rst by the
mircrocontroller is displayed on the screen.
mircrocontroller is displayed on the screen.
Display of POWER/STANDBY Flash Count
- One blink is not used for self-diagnosis.
- Example
Diagnosis item
Diagnosis item
LED blinks
Lamp cover
3 times
Fan
4 times
LED ON : 0.3sec
LED OFF : 0.3sec
LED OFF : 0.3sec
LED OFF
3.0sec
Stopping the POWER/STANDBY LED Flash
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the POWER/STANDBY lamp from fl ashing.
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the POWER/STANDBY lamp from fl ashing.
Self-Diagnostic Screen Display
For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confi rmed, it is possible to bring up past
occurrences of failure on the screen for confi rmation.
For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confi rmed, it is possible to bring up past
occurrences of failure on the screen for confi rmation.
To Bring Up Screen Test
In standby mode, press the buttons on the Remote Commander sequentially, in rapid succession, as shown below:
In standby mode, press the buttons on the Remote Commander sequentially, in rapid succession, as shown below:
Display
Channel 5
Sound Volume -
Power ON
Self-Diagnostic Screen Display
Self Diagnosis
SELF DIAGNOSIS
6 : +B OVP
0
1 : LAMP
0
7 : AUDIO
0
3 : LAMP COVER
0
8 : D-OVP
1
4
: FAN
1
101 : WDT
0
Move the joystick
4 : TEMP
0
5 : LAMP DRIVER
0
201 : WDT-ENGINE
0
- Numeral "1" means a fault was detected one time or more.
- Numeral "0" means that no fault was detected.
- Numeral "0" means that no fault was detected.
MAIN
LCD ENGINE
Handling of Self-Diagnostic Screen Display
Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen during repairs. When you
have completed the repairs, clear the result display to “0”.
Unless the result display is cleared to “0”, the self-diagnostic function will not be able to detect subsequent faults after completion of the repairs.
Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen during repairs. When you
have completed the repairs, clear the result display to “0”.
Unless the result display is cleared to “0”, the self-diagnostic function will not be able to detect subsequent faults after completion of the repairs.
9
KF-42WE620/50WE620
KF-42WE620/50WE620
Clearing the Result Display
To clear the result display to “0”, press the buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
To clear the result display to “0”, press the buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
1. Power off (Set to Standby model)
2. Display
Channel 5
Sound Volume -
Power ON
3. Channel 8
ENTER
4. Wait until the initial setup display appears.
5. Disconnect the AC plug and then reconnect it.
Quitting the Self-Diagnostic Screen
To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.
To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.
Self-Diagnostic Circuit
Self-Diagnosis Function Operation
- 3
- 3
: Lamp cover
If the lamp cover SW is opened then pin 1 of CN8034 on the A board is high. The LCD Engine u-com (pin 27 of
IC3208 on the C2 board) detects it and turns the lamp off.
IC3208 on the C2 board) detects it and turns the lamp off.
- 4
: Fan
If Fan1, Fan2, Fan3, or Fan4 stops then pin 2, 5, 8 or 11 of CN8035 on the A board is high. The LCD Engine
u-com (pin 24 of IC3208 on the C2 board) detects it and turns the lamp off.
u-com (pin 24 of IC3208 on the C2 board) detects it and turns the lamp off.
- 4
: Temp
If a temperature sensor on the H4 board detects a high temperature,
or the IIC-E line connector (CN8041:A board,CN3951 H4 board) is not attached securely, the LCD Engine u-
com IIC-E Line detects it and turns the lamp off.
or the IIC-E line connector (CN8041:A board,CN3951 H4 board) is not attached securely, the LCD Engine u-
com IIC-E Line detects it and turns the lamp off.
- 5
: Lamp drive
If a lamp is not turned on, then pin 29 of LCD Engine u-com (IC3208 on the C2 board) is high and checks pin
28 of LCD Engine u-com. If pin 28 is low, it is judged no high voltage.
28 of LCD Engine u-com. If pin 28 is low, it is judged no high voltage.
- 6
: +BOVP
If +17V line drops then pin 53 of MAIN u-com (IC3405 on the C2 board) is low and automatically turns off the
main power.
main power.
- 7
: Audio
If DC appears by the audio amp failure at the speaker line then it is detected by MAIN u-com (pin 59 of IC3405
on the C2 board) and automatically turns off the main power.
on the C2 board) and automatically turns off the main power.
- 8
: D-OVP
If +3.3V, +2.5V, or +1.8V line over, then pin 49 of MAIN u-com (IC3405 on the C2 board) is low and
automatically turns off the main power.
automatically turns off the main power.
- LAMP : Lamp
If a lamp is not turned on, then pin 29 of LCD Engine u-com (IC3208 on the C2 board) is high and checks pin
28 of LCD Engine u-com. If pin 28 is high the lamp is burned out.
28 of LCD Engine u-com. If pin 28 is high the lamp is burned out.
IC41
27
IIC-E
LAMP COV
28
29
24
LAMP DRV
LAMP PROT
FAN PROT
4:Temp
IC3208
LCD Engine u-com
IC3405
MAIN u-com
49
59
53
SP-DC-PROT
LOW-B-ERR
D-OVP
H3/A board
8:D-OVP
6:+B OVP
G3/A board
G1/A board
17V-DET
CN8014
3:Lamp
cover
5:Lamp
driver
Lamp
4:Fan
Lamp
HV-DET
SW
S3999
T/A board
LAMP-PRT
Fan1
Fan2
Fan3
CN8003
FAN1-PRT
FAN2-PRT
FAN3-PRT
CN8022
Audio
amp
Audio
amp
7:Audio
IC4704
IC8504
C2 board
AU board
A board
Lamp driver
Temp
sensor
+3.3V
+2.5V
+1.8V
+2.5V
+1.8V
+17V
1
2
3
1
2
8
5
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