Sony KV-21SE43C, KV-20S90 service manual SELF-DIAGNOSTIC Function, Self Diagnosis

KV-20S90 / 21SE43C

SELF-DIAGNOSTIC FUNCTION

Self Diagnosis

Supported model

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. No error has occurred if the screen displays a “0”.

Diagnostic Item	No. of times	Self-Diagnositc			Probable Cause Location	Detected Symptoms
Description	STANDBY/ TIMER		Display/
	lamp flashes	Diagnostic Result
Power does not turn on	Does not light			• Power cord is not plugged in.		• Power does not come on.
				• Fuse is burned out (F601). (A Board)		• No power is supplied to the TV.
						• AC Power supply is faulty.
+B overcurrent (OCP)*	2 times		2:0 or 2:1	•	H.OUT (Q502) is shorted.(A Board)	• Power does not come on.
				• IC1751 (C Board) is shorted.		• Load on power line is shorted.
Vertical Defl ection	4 times		4:0 or 4:1	•	+13V is not supplied. (A Board)	• Has entered standby state after horizontal raster.
Stopped				•	IC541 is faulty. (A Board)	• Vertical defl ection pulse is stopped.
						• Power line is shorted or power supply is stopped.
White Balance failure	5 times		5:0 or 5:1	•	Video OUT (Q392 to Q394) is faulty.	• No raster is generated.
(not balanced)					(A Board)	• CRT Cathode current detection reference pulse
				• IC301 is faulty. (A Board)
						output is small.
				• Screen (G2) is improperly

*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.

Display of Standby/Timer LED Flash Count

2 times 4 times

5 times

LED ON 0.3 sec.
	LED OFF
LED OFF 0.3 sec.
	3 sec.
Diagnostic Item		Flash Count*
+B Overcurrent		2 times
Vertical Defl ection Stopped 4 times
White Balance Failure		5 times

*One fl ash count is not used for self-diagnostic.

Stopping the Standby/Timer LED Flash

Standby/Timer LED

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.

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