SONY KDL26S2000 KDL40S2000 KDL46S2000_ SERVICE HELP [Part-1]

                                                 [1]
                                              STANDBY LIGHT BLINKS ONCE 
           Fault:  10.5V and panel 5V Low-Voltage protection

• Check that the Main Supply is developing 10.5V at CN6200 | CN6202 / pins 7&8.  The voltage should increase to 10.5V and should stabilize.  If this voltage is not present the main power board is defective, in this case, replace G1 | G2 board.
• If the 10.5V is present then determine if the panel 5V is being developed by the switching regulator IC7000 on the BU Board.  Check the voltage at TP-1 on the BU board, this is the 5V output of IC7000.  If the panels' 15V does not approach  15V before the TV shuts down, make sure that the regulator has failed.  Replace the 'BU" board.
• If both the 10.5V & panel 5V are OK, then the protection circuit [Q7500 & Q7502] should be checked.  If 3.1V is present at CN1001 | pin154, then the protection circuit is working properly and the main processor is not processing the signal correctly.  If 0V is present at pin 154 of IC CN1001, then the protection circuit failed.  In either case, the BU board has to be replaced. 

STANDBY LIGHT BLINKS TWICE

Fault: D5V under-voltage protection.

• There are only [2] failures that can cause two blinks of standby light to these sets.  [1]  Open PS7000. [2] Defective 5V [D5V] regulator IC 7005.
• Both these components are located on BU board and therefore would warrant are "BU" board replacement.  Anyway, for a possible quick and easy fix check for an open PS7000.  Replace if open. 
• If PS7000 is OK, then the output of the 5V regulator IC7005 should be check to confirm a BU board failure.  If the 5V is missing, replace BU board.  

STANDBY LIGHT BLINKS THRICE

Fault:  3.3V & 1.8V low voltage protection.

• There are four failures that can cause three blinks of standby light to theses sets.  [1] Open F7000. [2] Defective 3.3V regulator IC7001 [TP-3].  [3] Defective 1.8V regulator IC7002 [TP-2].  [4] Defective 2.4V regulator IC7004 [TP-4].
• If '0V' is present at any of the regulator output test points, of if F7000 is open, the replace the defective component or the BU board. 
• If F7000 and all voltages at test points stated above are OK, and TV still shuts down and show three standby light blinks at start up, a component in the protection circuit [Q7504|Q7505|Q7506|Q7503|D7508|D7509 & D7510] itself might have failed. 
• Check for the presence of 3.1V at IC1001/pin 163.  If 3.1V is present there, then the regulators and circuits are working properly.  The failure is most likely to the Main Micro-processor.  It might not processing the DC ALERT-1 signal properly.  No other way than replace the (BU) board.

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