Help identifing this part. Picture included.

[seajayemm]

I bought this non working Vizio tv, opened it up and found a bad voltage regulator (circled in the picture). I was getting a reading of .58v on the adjustment leg. I have searched the past 3 days on the internet for a replacement but have gotten nowhere.
IIC?
1084
0808BL
is printed on the top of it.
I would appreciate any help identifying a replacement for this. Thanks in advance.

[budm]

Re: Help identifing this part. Picture included.

What is the output between the Adj and the Output pin, it should be 1.25V.
Are there 1 resistor connected between the adj and Ground, and another one between Adj and Out pin? What do you have at Input?

[seajayemm]

Re: Help identifing this part. Picture included.

I have labeled the voltage readings for the regulators in the picture. I found another (smaller one) that has a 0.00v reading on the adjustment leg.

[seajayemm]

Re: Help identifing this part. Picture included.

When plugged in the Vizio power indicator is lighted orange, when powered the orange turns to white, the back light fires up. The screen lights up gray. I get no response from the power, volume, channel, etc buttons on the side once turned on. I would rather pay a few bucks to repair the board than dishing out $100 for a replacement board.

[seajayemm]

Re: Help identifing this part. Picture included.

Thread can be closed. I found the faulty regulator and just paid for a replacement. Will post back the results after I slap it in.

[PeteS in CA]

Re: Help identifing this part. Picture included.

I'm going to guess that the faulty part was an LT1084 or a clone thereof.

[seajayemm]

Re: Help identifing this part. Picture included.

I suspected the regulator with the red star was at fault reading 0.00v on adjustment pin, 1.25v on the output pin and 2.06v on the input pin. I swapped a new one in and now getting a reading of 0.00v on adjustment pin, 1.25v on the output pin and 2.06v on the input pin. Anyone have any input on this?

[mariushm]

Re: Help identifing this part. Picture included.

2v is uncommon, should be at least 2.5v or 3.3v, or 5v...

The linear regulator needs at least about 1v-1.3v above its set output voltage to give stable output voltage, so it's not possible to output 1.8v from 2v.

Follow the trace going to the input pin, measure the voltage at various points, see where that 2v comes from.

For example, the 2v could be coming from the power supply and was supposed to be 3.3v or some voltage, but a capacitor has failed somewhere and made the voltages go all over the place.
The easiest way to check this, is to measure the voltage on the connector coming from the power supply.

Ah, looking back at the picture I see 3.3v, 1.82v , 1.25v ... so yeah, follow the input pin and discover why it's so low value. Measure the other voltages...

Here's a good video in which the guy has a similar problem, low voltage on one of the power supply outputs.. :

http://www.youtube.com/watch?v=8k27lQFpNZs

Look how he measures the voltages and how he reasons and see if it helps you.

[seajayemm]

Re: Help identifing this part. Picture included.

Got tired of messing with it. Went ahead and ordered a new main board. Should get it back Friday, will post results after I swap them out.

[mariushm]

Re: Help identifing this part. Picture included.

Yeah, well if the power supply board is bad, that board with the voltage regulator will still see 2 volts.
Won't hurt you anything to measure some voltages while you wait.

[seajayemm]

Re: Help identifing this part. Picture included.

I measured voltages coming into the main board (the board I ordered) I found no readings of lower than 3.3vs. When I put the new board in I will take some more readings and compare them with the old board and try to pinpoint the problem, then repair the old board.

[selldoor]

Re: Help identifing this part. Picture included.

I measured voltages coming into the main board (the board I ordered) I found no readings of lower than 3.3vs. When I put the new board in I will take some more readings and compare them with the old board and try to pinpoint the problem, then repair the old board.

The output from the regulator old and new seems to be correct at 1.25v
(as Budm say in post2)

As in Post8 you need to trace from the 3.3 you say is coming in to the board to the regulator BUT if the output is 1.25v and that is correct it doesnt really matter?

[seajayemm]

Re: Help identifing this part. Picture included.

The person I bought the main board from said he could not test it completely and guarantee it was 100% good so he refunded me my money. He also told me his technician said that 90% of these models tvs have problems with the daughter board, that most people replaced the main board to not fix the problem. So I ordered a daughter board from shopjimmy for a third of the price of a main board. For now I will patiently wait for it to arrive.