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Self-diagnostic Function - Sony KV-21FS105 Service Manual

Trinitron color television.
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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.
Diagnostic Item
Power does not turn on
+B overcurrent (OCP)*
Vertical deflection stopped*
White balance failure
(not balanced)
* 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.
Display of Standby/Timer LED Flash Count
2 times
4 times
5 times
LED ON 0.3 sec.
LED OFF 0.3 sec.
Diagnostic Item
+B Overcurrent
White Balance Failure
*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.
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.


No. of Times
Self-Diagnostic Display/
Diagnostic Result
LED Flashes
Does not light
2:0 or 2:1
4:0 or 4:1
5 times
:0 or 5:1
3 sec.
Flash Count*
2 times
4 times
5 times
Probable Cause
• Power cord is not plugged in.
• Fuse is burned out. (F601) (A Board)
• H.OUT (Q502) is shorted. (A Board)
• IC702 is shorted. (CB Board)
• +12V is not supplied. (A Board)
• IC502 is faulty. (A Board)
• Video OUT (IC502) is faulty. (A Board)
• IC1301 is faulty. (MB Board)
• Screen (G2) is improperly adjusted.**
Self Diagnosis
Supported model
Detected Symptoms
• Power does not come on.
• No power is supplied to the TV.
• AC power supply is faulty.
• Power does not come on.
• 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 detection reference
pulse output is small.
Standby/Timer LED


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