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KV-27FV300
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82
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Service Manual
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Device
TV
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kv-27fv300.pdf
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Sony KV-27FV300 Service Manual ▷ View online

— 6 —
KV-27FV300/29FV300/32FV300/36FV300 
SAFETY CHECK-OUT
After correcting the original service problem, perform the following 
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.
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.
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.
5.  Look for parts which, though functioning, show obvious signs of 
deterioration. Point them out to the customer and recommend their 
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.
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 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.
1.  A commercial leakage tester, such as the Simpson 229 or 
RCA WT-540A. Follow the manufacturers’ instructions to use these 
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).
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.
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).
To Exposed Metal
 Parts on Set
AC Voltmeter
(0.75 V)
Earth Ground
0.15 
µF
1.5 k
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-27FV300/29FV300/32FV300/36FV300 
SELF-DIAGNOSTIC FUNCTION
Display of Standby/Timer LED Flash Count
3 times
2 times
4 times
5 times
9 times
10 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
LED OFF
3 sec.
 Diagnostic 
Item 
 Flash 
Count*
 +B 
Overcurrent 
 2 
times
 +B 
Overvoltage 
 3 
times
 V-STOP 
  4 
times
 IK 
(AKB) 
  5 
times
 Zero 
Cross  9 
times
 9V 
 
  10 
times
*One fl ash count is not used for self-diagnostic.
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.
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.
Results for all of the following diagnostic items are displayed on screen. If the screen displays a “0”, an error has occurred.
Self Diagnosis
Supported model
Standby/Timer LED
Diagnostic Item
No. of times
STANDBY / TIMER
lamp flashes
Probable Cause Location
Detected Symptoms
Power does not turn on
Does not light
• Power cord is not plugged in.
• Fuse is burned out (F601). (GK Board)
• Power does not come on.
• No power is supplied to the TV.
• AC Power supply is faulty.
+B overcurrent (OCP)*
2 times
• H.OUT (Q502) is shorted. (A Board)
• IC702 is shorted. (C Board)
• Power does not come on.
• Load on power line shorted.
+B overvoltage (OVP)
3 times
• IC501 is faulty. (A Board)
• If a high is supplied to pin 2 of IC501.
(A Board)
• Has entered standby mode.
I-Prot
4 times
• +12V is not supplied. (A Board)
• IC561 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.
IK (AKB)
5 times
• Video OUT (IC561) is faulty. (A Board)
• IC702 is faulty. (C Board)
• Screen (G2) is improperly adjusted. **
• No raster is generated.
• CRT Cathode current detection
reference pulse output is small.
Zero Cross
9 times
• No zero cross pulses on pin 45
IC1001. (A Board)
• Power does not come on.
9V Check
10 times
• Relay failed (RY600)
• Power does not come on.
* If a +B overcurrent is detected, stoppage of the vertical deflection is detected simultaneously. The symptom that is diagnosed first
by the microcontroller is displayed on the screen.
** Refer to Screen (G2) Adjustments in Section 2-4 of this manual
— 8 —
KV-27FV300/29FV300/32FV300/36FV300 
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.
To Bring Up Screen Test
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
DISPLAY   
 Channel  5   
 Sound volume  -   
 Power ON.
Numeral “0” means that no fault was detected.
Numeral “1” means a fault was detected one time only.
 SELF 
DIAGNOSIS
 2:  +B 
OCP 
 
0
 3:  +B 
OVP 
 
0
 4:  VSTOP 
 
0
 5:  AKB 
 
1
 9:  ZCD 
 
0
 10: 9VON 
 
0
 101: 
WDT 
 
0
  Serial: 
xxxxxxx
  Model: 
xxxxxxx
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.
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:
 
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.
Self-Diagnostic Circuit
A BOARD
IC301
Y/CHROMA JUNGLE
A BOARD
IC561
V. OUT
TO V BOARD
Q904 
BASE
A BOARD
Q651
A BOARD
IC001
SYSTEM
A BOARD
IC003
MEMORY
IK-AKBIN
VM-OUT
FROM
C BOARD
IC702 PIN 5
FROM
A BOARD
Q003 
COLLECTOR
HP(HLDWN)
SDA
A BOARD
FROM
Q530
33
O-LED
REF
I-OCP
IO-BDAT
BDA
DISPLAY
36
48
31
3
61
27
59
26
5
— 9 —
KV-27FV300/29FV300/32FV300/36FV300 
+B overcurrent (OCP) 
Occurs when an overcurrent on the +B (135V) line is detected by pin 48 of IC001 (A Board). If the voltage of pin 48 of IC001 (A Board) is less than 1V 
when V.SYNC is more than seven verticals in a period, the unit will automatically turn off. 
+B overvoltage (OVP) 
Occurs when a high is felt onpin 2 of IC501 (A Board).
I-PROT 
Occurs when an absence of the vertical defl ection pulse is detected by pin 31 of IC301 (A Board). Power supply will shut down when waveform 
interval exceeds 2 seconds. 
IK (AKB) 
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC301 (A 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).
Zero Cross
Check Q691 collector (GK Board) 7.5V STBY goes to 0V when the set is turned on. 
9V Check
Check Q691 collector (GK Board) 7.5V STBY goes to 0V when the set is turned on.
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