Hello everyone. I have used this forum to troubleshoot the problem with my TV. I have a 42" Vizio SV420M that was in standby when a lightning strike hit nearby. After that moment, the TV would no longer power on. The orange Vizio logo lights up when plugged in, but there is no response to power button on TV or remote. Upon reading numerous topics on BadCaps with the same symptoms on Vizio's, I am in the process of eliminating potential problem parts. I ordered a replacement power supply board and had the same symptoms, so returned the power supply board. I then began to look into the well known issue with voltage regulators on the main board. Following are the readings taken from the main board with unit plugged in, but not on.
Vizio SV420M
0500-0407-0890
DPS-260JP C
LC420WUF-SBA1
3642-0802-0150 6B
Voltage Regulators:
U5 L334 G1084
In 5.13 V
Out 3.27 V
GND 2.02 V
U3 L334 G1084
In 5.13 V
Out 3.27 V
GND 2.02 V
U4 L271 G9117
In 3.26 V
Out 1.22 V
ADJ 0 V
U2 L271 G9117
In 5.16 V
Out 3.26 V
ADJ 2.01 V
U7 L271 G9117
In 5.13 V
Out 3.25 V
ADJ 2.00 V
U6 L271 G9117
In 12.22 V
Out 8.09 V
ADJ 6.84 V
U8 7805CT RAQ941G
In 12.22 V
Out 0 V
GND 5.00 V
U9 L331 G1084
In 3.29 V
Out 1.79 V
GND 0.54 V
Power button:
2.32 V when open (unpressed)
2.26 V when closed (pressed down)
I have read about reflowing the main board due to poor solder joints, about the potential for the EEPROM to be corrupt, and also about the potential for bad caps. The caps appear normal with no bulging or leaking, however, they have not been tested for shorts. Based on the values above, can anyone see any problem regulators, or do I move on to reflow, then possibly EEPROM? I appreciate any and all help!
Vizio SV420M
0500-0407-0890
DPS-260JP C
LC420WUF-SBA1
3642-0802-0150 6B
Voltage Regulators:
U5 L334 G1084
In 5.13 V
Out 3.27 V
GND 2.02 V
U3 L334 G1084
In 5.13 V
Out 3.27 V
GND 2.02 V
U4 L271 G9117
In 3.26 V
Out 1.22 V
ADJ 0 V
U2 L271 G9117
In 5.16 V
Out 3.26 V
ADJ 2.01 V
U7 L271 G9117
In 5.13 V
Out 3.25 V
ADJ 2.00 V
U6 L271 G9117
In 12.22 V
Out 8.09 V
ADJ 6.84 V
U8 7805CT RAQ941G
In 12.22 V
Out 0 V
GND 5.00 V
U9 L331 G1084
In 3.29 V
Out 1.79 V
GND 0.54 V
Power button:
2.32 V when open (unpressed)
2.26 V when closed (pressed down)
I have read about reflowing the main board due to poor solder joints, about the potential for the EEPROM to be corrupt, and also about the potential for bad caps. The caps appear normal with no bulging or leaking, however, they have not been tested for shorts. Based on the values above, can anyone see any problem regulators, or do I move on to reflow, then possibly EEPROM? I appreciate any and all help!
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