Sony KV-25FS150 (serv.man2) Service Manual ▷ View online
KV-25FS150
KV-25FS150
5
WARNINGS AND CAUTIONS
CAUTION
Short circuit the anode of the picture tube and the anode cap to the metal chassis, CRT shield, or carbon painted on the CRT, after
removing the anode.
removing the anode.
WARNING!!
An isolation transformer should be used during any service to avoid possible shock hazard, because of live chassis. The chassis of this
receiver is directly connected to the AC power line.
receiver is directly connected to the AC power line.
!
SAFETY-RELATED COMPONENT WARNING!!
Components identifi ed by shading and ! mark on the schematic diagrams, exploded views, and in the parts list are critical for safe
operation. Replace these components with Sony parts whose part numbers appear as shown in this manual or in supplements published
by Sony. Circuit adjustments that are critical for safe operation are identifi ed in this manual. Follow these procedures whenever critical
components are replaced or improper operation is suspected.
operation. Replace these components with Sony parts whose part numbers appear as shown in this manual or in supplements published
by Sony. Circuit adjustments that are critical for safe operation are identifi ed in this manual. Follow these procedures whenever critical
components are replaced or improper operation is suspected.
KV-25FS150
KV-25FS150
6
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.
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.
leakage as 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.
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
0.15 μF
1.5 K
Ω
AC
Voltmeter
(0.75 V)
Earth Ground
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.
KV-25FS150
KV-25FS150
7
SELF-DIAGNOSTIC FUNCTION
*One fl ash count is not used for self-diagnostic.
*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.
**Refer to Screen (G2) Adjustments in Section 2-4. of this manual.
is displayed on the screen.
**Refer to Screen (G2) Adjustments in Section 2-4. of this manual.
2. Display of STANDBY LED Flash Count
2 times
4 times
5 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
LED OFF
3 sec.
Standby indicator
Self Diagnosis
Supported model
The units in this manual contain a self-diagnostic function. If an error occurs, the STANDBY LED indicator 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 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 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.
1. Diagnostic Test Indicators
When an error occurs, the STANDBY LED indicator will fl ash a set number of times to indicate the possible cause of the problem. If there is more than
one error, the indicator 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”.
one error, the indicator 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”.
Diagnosis
Item
Description
• No Power
• +B overcurrent
(OCP)
• Vertical NG.
• IK (AKB)
• Supply Voltage
Protection
Detected
Symptoms
• Power does not turn on.
• No power is supplied to the
• No power is supplied to the
TV.
• AC power supply is faulty.
• Power does not turn on.
• Load on power line is
• Load on power line is
shorted.
• Has entered standby state
after horizontal raster.
• Vertical deflection pulse is
stopped.
• Power line is shorted or
power supply is stopped.
• No raster is generated.
• CRT cathode current
• CRT cathode current
detection reference pulse
output is small.
output is small.
• No power supply to CRT
ANODE.
• No RASTER is generated.
No. of times
STANDBY
Indicator flashes
Does not light
2 times
4 times
5 times
8 times
Diagnostic Result
on screen display
—
2 OCP:0
2 OCP:1 ~ 255
4 VSTOP:0
4 VSTOP:1 ~ 255
5 AKB:0
5 AKB:1 ~ 255
8 SUP:0
8 SUP:1 ~ 255
Probable
Cause
Location
• Power cord is not plugged
in.
• Fuse is burned out (F4101)
(H2 Board)
• H.OUT (Q511) is shorted.
(A board)
• IC751 is shorted.
(CV Board)
• +13V is not supplied.
(A Board)
• IC503 voltage list is faulty.
(A Board)
• Video OUT (IC751) is faulty.
(CV Board)
• IC001 is faulty. (A Board)
• Screen (G2) is improperly
• Screen (G2) is improperly
adjusted.
• IC604 faulty.
• IC607 faulty.
• IC607 faulty.
KV-25FS150
KV-25FS150
8
3. Stopping the STANDBY LED Indicator Flash
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY LED Indicator from fl ashing.
Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY LED Indicator from fl ashing.
4. 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 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
Note that this differs from entering the Service Mode (Sound Volume + ).
The following screen will be displayed indicating the error count:
SELF DIAGNOSTIC
2 OCP
: 0
3 OVP
:
N/A
4 VSTOP :
0
Number “0” means that no fault was detected.
5 AKB
:
1
Number “1” means a fault was detected one time only.
8 SUP
:
0
101 WDT
:
N/A
SERIAL: FFFFFFF
MODEL: FFFFFFFF
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:
Channel 8
0
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.
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