Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

[organizddisastr]

Hey everybody, I was wondering if anyone could help me. I replaced the U33 and U9 chip. During U33 replacement I lost a small resister behind U33 so I simply bridged the resistor. The TV worked fine for about a week and one night while watching a movie the picture became pixelated. It almost looks like a bad youtube video and static. Here are some pictures. The bridged resister the second one to the right of R30. Any ideas or any help would be greatly appreciated. Thanks in advance.

[Paul678]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

Hey everybody, I was wondering if anyone could help me. I replaced the U33 and U9 chip. During U33 replacement I lost a small resister behind U33 so I simply bridged the resistor. The TV worked fine for about a week and one night while watching a movie the picture became pixelated. It almost looks like a bad youtube video and static. Here are some pictures. The bridged resister the second one to the right of R30. Any ideas or any help would be greatly appreciated. Thanks in advance.

You "bridged" a lost resistor, as in you just shorted it out
with a piece of wire?

That's a really BAD idea! Now you have likely ruined another
portion of the circuit.

Can you find out what the original value was? And replace it?

[organizddisastr]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

I simply connected the two points with a small line of solder, bypassing it. I suppose I could read the resistance on the one next to it and try to get one identical to it. Its the size of a flea. (Not easy to solder) I'm a noob at this stuff. A friend gave me the TV for free, so what better way to learn then on something I got for nothing.

[tom66]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

I simply connected the two points with a small line of solder, bypassing it. I suppose I could read the resistance on the one next to it and try to get one identical to it. Its the size of a flea. (Not easy to solder) I'm a noob at this stuff. A friend gave me the TV for free, so what better way to learn then on something I got for nothing.

Its neighbour is probably a different value. Your best bet is a schematic or someone else with a similar board.

[Paul678]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

I simply connected the two points with a small line of solder, bypassing it. I suppose I could read the resistance on the one next to it and try to get one identical to it. Its the size of a flea. (Not easy to solder) I'm a noob at this stuff. A friend gave me the TV for free, so what better way to learn then on something I got for nothing.

Well, just for the future, you shoudn't bypass a resistor with a
short, unless you really understand the circuit, and have determined
it's safe to do so.

Yes, you should try to find a schematic and determine what the
original value was. It may be too late for the other parts of the
circuit that may have been damaged, but that would be a first step....

[budm]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

Those 3-pin devices are adjustable voltage regulator, the output voltage is set by the two resistors connected to the left pin of the IC. See LM1117 for example. Why ase they replaced in the first place?
Failed TV's and Monitors: http://s807.photobucket.com/albums/yy352/budm/

[PlainBill]

Re: Vizio GV42LHDTV10A Pixelated Picture Problems After U33 Replacement

What is the value of the remaining resistor? Double check this, but I believe U33 usually outputs 3.3 volts. Searching for U33 Vizio on this site will give you the correct voltage. The calculation is Vout = 1.25 x (1 + R1/R2). R1 is the resistor between pin 1 and pin 2, R2 is the resistor between pin 1 and Gnd.

PlainBill