SONY KDL32EX SERIES LCD TVS - HOW TO TROUBLESHOOT THE POWER SUPPLY SECTION

Sony KDL32EX series LCD TVs - How to troubleshoot the Power supply Section

Applicable to Sony KDL-32EX301 KDL-32EX500 KDL-46EX400 KDL-32EX400 KDL-40EX500 KDL-46EX500 KDL-40EX400 KDL-40EX501 KDL-46EX501 KDL-40EX401

Power [SMPS] Troubleshooting
110VAC is applied to the G2LE-Board, G2HE-Board, or GD2-Board it can be measured at CN6101 or CN6003. In the standby mode the AC power passes through the main fuse F6101 or F6001. The is no main relay on the G2LE & G2HE-Board so the AC power is applied directly to the Main & Standby Power supply. The GD2-Board does have a Main AC Relay.  The AC power passes through R6003 (Inrush resistor), and D6001 and is applied to the Main DC/DC Converter IC6501 and the Standby DC/DC Converter IC6201. IC6501 is not active in the standby mode. However, IC6201 is active in standby mode and outputs STBY 3.3Vdc as long as AC power is applied to the TV. The Standby 3.3Vdc is supplied to the TVMicroprocessor, Switch Unit (Power Key), and HSR-Board (IR Sensor) in the standby mode.
Once a ON command is received form the remote controller or the power button on the Switch Unit the TV-Microprocessor outputs the Power-ON signal. The Power-On signal is applied to the G2LE-Board, G2LE-Board, or GD2-Board. On the power supply board the Power-On signal switches the 19V from the standby power supply to activate the PFC and Main Power supply IC6501. No relay click will be heard on the 32” or 40” models because there is not a main relay. However, on the 46” models there is a main relay and one relay click is heard at power-on. The relay engages to bypass the inrush resistor R6003 during the ON state.

The main power supply IC6501 is now active and outputting all secondary supplies. The 12Vdc secondary is the supply voltage for all the voltage regulators on the A-Board. The AU12V is the supply voltage for the audio output amplifier. The 32” and 40” models power supply will also output 24V which is the supply voltage for the backlight inverter board.  The GD2-Board in the 46” models will develop and output the backlight high-voltage (1KV) to the Balancer board and the CCFL backlights.
No Power/Dead Set (No RED Standby LED)
In a dead set condition there will be No RED Standby LED illumination in the Standby Mode (TV plugged into an active AC Outlet).  The following bullet list gives the possible failures for a “No Power/Dead Set” condition.

> Loss of AC Power
> Loss of AC-OFF-DET
> Loss of Standby 3.3Vdc
> Loss of REG12V
> Loss of Power-On
> Defective Main Microprocessor

The first step in troubleshooting a “No Power/Dead Set” condition is to confirm that 110ACV power from an active AC outlet is applied to the G2LE-Board, G2LE-Baord, or GD2-Board. AC power is applied to, and can be measured at CN6101 on the G2BE-Board or G2CE-Board and at CN6003 on the GD2-Board.
Next, check for the presence of the AC-OFF-DET voltage at CN6401/pin 2 or CN6150/pin 2. If the AC-OFF-DET circuit is working properly 3V should be measured. If the 3V is not present replace the G2BE-Board, G2CEBoard, or GD2-Board. If the 3V in not present either the main fuse or the main power supply IC6501 is defective. In either case, replace the power supply board.

After confirming the AC power and AC-OFF-DET, check for a defective Standby 3.3Vdc power supply IC6201. To confirm a defective IC6201 check the 3.3V secondary voltage at CN6401/pin 1 or CN6150/pin 1.  As long as AC power is applied to the TV IC6201 should be active and outputting 3.3Vdc. If the 3.3V is not present then IC6201 is defective.  Replacing the power supply board will fix the problem.

Finally, a “Dead Set” condition can be caused by a defective microprocessor IC400. The microprocessor outputs the Power-On signal which activates

the switch Q6301 and IC6301 on the power supply board and passes the 19V from the Standby power supply to active the relay (46” models), PFC, and Main Power Supply IC6501. If the Power-On signal is not output after receiving the Power-ON command the power supply board circuits remain inactive and a “Dead Set” condition exists. The Power-On signalcan be checked at CN6401/pin 3 or CN6150/pin 3. It should measure approximately 3.3Vdc If the measurement is 0Vdc before shut-off the TV microprocessor is defective. Replace the A-Board. If the power-on voltage is 3V before shutdown then the switch circuit on the power supply board is defective. Replace the power supply board.

G2LE-BOARD & G2HE-BOARD CONNECTOR DIAGAM: 32” & 40” POWER SUPPLY SYSTEM

46 inch POWER SUPPLY SYSTEM