I don't think this is a capacitor problem but I didn't "unsolder and check the capacitor's with a meter" because by all appearance they look ok (I know, this doesn't positively mean they are ok)! I am not a professional, just trying to save on repair expenses (I hope).
I have a Vizio Model VO420E, 42" LCD. Have a problem like a lot of people mention having: Plug TV into receptacle and yellow Vizio name shows up. Push power button on remote, or the power button on side, and the Vizio name turns from yellow to white. The white Vizio name continues to remain white,,,,,,,but the screen is black and no sound. After reading a lot of different threads on the internet, felt sure I would find bulged or exploded electrolytic capacitors when I removed the back and checked the boards. I was so sure that I bought replacements in advance!!! After visually checking all capacitors on both the boards, I can find NONE that look like they are bad. I didn't actually check any of them with the meter, but feel they are ok! Now what, I thought. The next most popular fix seemed to be the U33 position on the Main Board. Everyone said the U33 part was "amc1117", a 1A Low Dropout Positive Regulator which should register 3.3 volts. After finding the U33 position on my main board (#0171-2271-2855) I find that instead of a power regulator, there is a bigger square chip with about twelve lead coming out of it on all four sides. After googling the part number (TPA3101D2) that there is a power amplifier in the U33 position on my board. I do find six, of what I believe are the regulators on the main board, but none in the U33 position. I checked the voltage on all of these and am posting them below:
U2 - 5.10v, 3.30v, 2.05v
U4 - 5.14v, 3.30v, 2.05v
U5 - 5.10v, 2.63v, 1.37v
U8 - 3.27v, 1.24v, 0.00v
U9 - 5.10v, 2.51v, 1.25v
TU31 - 0.0v, .47v, 0.0v not sure why it has a TU?
Since some of the the above voltage regulators are showing the correct voltage, I presume that my problem "is on" the main board and not the power supply board. Could you give me the voltage that these regulators "should" be showing? I have no schematics or anything else to go by.
I had a little electronics training "years ago" but don't remember a whole lot. I'm not an expert by any means in electronics and would appreciate any help (what so ever) on this problem. Since I have a power amplifier in the U33 position,,,,,,,,,,,then which position on my board would hold the suspected bad voltage regulator that is in the U33 position on all these other boards?? Also, any other ideas of which part could be bad, would also be greatly appreciated! I have also seen posts on other boards where a person with these same symptoms as mine, have replaced both the voltage supply board, and the main board, and still did not fix this problem.
I have a Vizio Model VO420E, 42" LCD. Have a problem like a lot of people mention having: Plug TV into receptacle and yellow Vizio name shows up. Push power button on remote, or the power button on side, and the Vizio name turns from yellow to white. The white Vizio name continues to remain white,,,,,,,but the screen is black and no sound. After reading a lot of different threads on the internet, felt sure I would find bulged or exploded electrolytic capacitors when I removed the back and checked the boards. I was so sure that I bought replacements in advance!!! After visually checking all capacitors on both the boards, I can find NONE that look like they are bad. I didn't actually check any of them with the meter, but feel they are ok! Now what, I thought. The next most popular fix seemed to be the U33 position on the Main Board. Everyone said the U33 part was "amc1117", a 1A Low Dropout Positive Regulator which should register 3.3 volts. After finding the U33 position on my main board (#0171-2271-2855) I find that instead of a power regulator, there is a bigger square chip with about twelve lead coming out of it on all four sides. After googling the part number (TPA3101D2) that there is a power amplifier in the U33 position on my board. I do find six, of what I believe are the regulators on the main board, but none in the U33 position. I checked the voltage on all of these and am posting them below:
U2 - 5.10v, 3.30v, 2.05v
U4 - 5.14v, 3.30v, 2.05v
U5 - 5.10v, 2.63v, 1.37v
U8 - 3.27v, 1.24v, 0.00v
U9 - 5.10v, 2.51v, 1.25v
TU31 - 0.0v, .47v, 0.0v not sure why it has a TU?
Since some of the the above voltage regulators are showing the correct voltage, I presume that my problem "is on" the main board and not the power supply board. Could you give me the voltage that these regulators "should" be showing? I have no schematics or anything else to go by.
I had a little electronics training "years ago" but don't remember a whole lot. I'm not an expert by any means in electronics and would appreciate any help (what so ever) on this problem. Since I have a power amplifier in the U33 position,,,,,,,,,,,then which position on my board would hold the suspected bad voltage regulator that is in the U33 position on all these other boards?? Also, any other ideas of which part could be bad, would also be greatly appreciated! I have also seen posts on other boards where a person with these same symptoms as mine, have replaced both the voltage supply board, and the main board, and still did not fix this problem.
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