Solved: 42 inch Vizio LCD TV would power on (green led) then power off immediately (red led flashing).

Upon troubleshooting 4 electrolytic caps were bulged 2 on each inverter board. The slave inverter board also had a shorted inverter IC, which was shorted at the error-amp pins, the inverter IC part# was BD9883AF. The slave inverter board also had 4 bad mosfets, 3 shorted & 1 had no output, mosfet part# was FDD8447L.

VIZIO TV REPAIR

After replacing the inverter IC and mosfets, here you can see a good oscillator input signal.

VIZIO TV REPAIRING
The pwm_sync signal and oscillator burst signal are perfect alignment.

The drive frequency for the eefl backlights is in great standing, along side the burst signal (very important).

Perfect sinewave in sync with burst signal, no glitches or pinching.

These are the new mosfets that were being used on the slave inverter before testing waveforms for proper values.

vizio lcd tv troubleshooting

Here are the final results of component level servicing and strict waveform testing. The tv has a beautiful picture and good 'white balance' and great color detail.

It very important to use digital scopes with todays high-speed signals in LCD TV's, using the scope allows the technician to see how the circuits communicate with each other during power up, operation, and power down.

You can learn much more in my new E-book LCD TV Repair Secrets which is filled with troubleshooting methods and trade secrets behind LCD TV servicing techniques.

Happy repairing : Damon Morrow