Sony KV-21FS105 (serv.man2) Service Manual ▷ View online
6
KV-21FS105
KV-21FS105
SAFETY CHECK-OUT
After correcting the original service problem, perform the following safety
checks before releasing the set to the customer:
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.
sets 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.
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
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).
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).
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
AC Voltmeter
(0.75 V)
(0.75 V)
Earth Ground
0.15
µ
F
1.5
k
Ω
g
AC Outlet Box
Ohmmeter
Cold-water Pipe
Figure A. Using an AC voltmeter to check AC leakage.
Figure B. Checking for earth ground.
7
KV-21FS105
KV-21FS105
SELF-DIAGNOSTIC FUNCTION
Display of Standby/Timer LED Flash Count
2 times
4 times
5 times
4 times
5 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
LED OFF 0.3 sec.
LED OFF
3 sec.
Diagnostic Item
Flash Count*
+B Overcurrent
2 times
V-STOP
4
times
White Balance Failure
5 times
*One fl ash count is not used for self-diagnostic.
Stopping the Standby/Timer LED Flash
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY/TIMER LAMP from fl ashing.
Stopping the Standby/Timer LED Flash
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY/TIMER 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.
The units in this manual contain a self-diagnostic function. If an error occurs, the STANDBY/TIMER LED 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 STANDBY/TIMER LED 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 STANDBY/TIMER LED 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 STANDBY/TIMER LED 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.
When an error occurs, the STANDBY/TIMER LED 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. If the screen displays a “0”, an error has occurred.
Diagnostic Item
Description
No. of Times
STANDBY/TIMER
LED Flashes
Self-Diagnostic Display/
Diagnostic Result
Probable Cause
Location
Detected Symptoms
Power does not turn on
Does not light
• Power cord is not plugged in.
• Fuse is burned out. (F601) (A Board)
• Power does not come on.
• No power is supplied to the TV.
• AC power supply is faulty.
+B overcurrent (OCP)*
times
2:0 or 2:1
• H.OUT (Q502) is shorted. (A Board)
• IC702 is shorted. (CB Board)
• Power does not come on.
• Load on power line is shorted.
Vertical deflection stopped*
times
4:0 or 4:1
• +12V is not supplied. (A Board)
• IC502 is faulty. (A Board)
• Has entered standby state after horizontal raster.
• Vertical deflection pulse is stopped.
• Power line is shorted or power supply is stopped.
White balance failure
(not balanced)
(not balanced)
5 times
:0 or 5:1
• Video OUT (IC502) is faulty. (A Board)
• IC1301 is faulty. (MB Board)
• Screen (G2) is improperly adjusted.**
• No raster is generated.
• CRT cathode current detection reference
pulse output is small.
2
4
5
* If a +B overcurrent is detected stoppage of the vertical defl ection is detected simultaneously.
The symptom that is diagnosed fi rst by the microcontroller is displayed on the screen.
** Refer to Screen (G2) Adjustments in Section 2-4. of this manual.
Self Diagnosis
Supported model
Standby/Timer LED
8
KV-21FS105
KV-21FS105
To Bring Up Screen Test
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
DISPLAY
Channel 5
Sound volume -
Power ON.
SELF
DIAGNOSIS
2:
0
3: NA
0
4:
0
Numeral “0” means that no fault was detected.
5: NA
1
Numeral “1” means a fault was detected one time only.
101:
WDT
0
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.
Clearing the Result Display
To clear the result display to “0”, press buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
To clear the result display to “0”, press buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
ENTER
Channel 8
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
MB BOARD
IC1301
Y/CHROMA JUNGLE
A BOARD
IC507
V. OUT
MB BOARD
IC1001
SYSTEM
MB BOARD
IC1003
MEMORY
IK IN
FROM
CRT
21
HP/PROTECT
SDA
A BOARD
FROM
IC502
PIN 7
18
35
IO-SDAT
O-LED
37
REF 3
I-PROT
IO-BDAT
17
36
B-DAT
5
18
DISPLAY
+B overcurrent (OCP)
Occurs when an overcurrent on the +B (135V) line is detected by pin 18 of IC1301 (MB Board). If the voltage of pin 18 of IC1301 (MB Board) is less than
1V when V.SYNC is more than seven verticals in a period, the unit will automatically turn off.
Occurs when an overcurrent on the +B (135V) line is detected by pin 18 of IC1301 (MB Board). If the voltage of pin 18 of IC1301 (MB Board) is less than
1V when V.SYNC is more than seven verticals in a period, the unit will automatically turn off.
Vertical Deflection Stopped
Occurs when an absence of the vertical defl ection pulse is detected by pin 17 of IC1001 (MB Board). Power supply will shut down when waveform interval
exceeds 2 seconds.
Occurs when an absence of the vertical defl ection pulse is detected by pin 17 of IC1001 (MB 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 IC1301 (MB Board). TV will stay on, but
there will be no picture.
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC1301 (MB Board). TV will stay on, but
there will be no picture.
*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K).
9
KV-21FS105
KV-21FS105
SECTION 1: DISASSEMBLY
1-1. REAR COVER REMOVAL
1-2. CHASSIS ASSEMBLY REMOVAL
1-3. SERVICE POSITION
Screw +BVTP 4x16
Screw +BVTP 4x16
Rear Cover
Screw +BVTP 4x16
Screw +BVTP 4x16
CB Board
A Board
MB Board
Claw
MB Board
A Board
CB Board
Extension Cable
for Service
p/n S-1294-965-A
for Service
p/n S-1294-965-A
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