Vizio LDO Voltage Reg VW42LHDTV10A

[Ltank]

Well I read up allthe other post on the site. The Yellow standby light comes on and then turns white when turned on but no 12 or 24vdc. The main board is 3642-0262-0150. I checked the LDO and other voltage regulators.
U2 5.12 3.31 2.07
U8 5.12 3.28 2.05
U33 5.12 3.32 2.07
U7 3.32 1.11 .02 ---- Bad output and is the input voltage correct?
U9 3.32 1.51 .001---- Is the input voltage correct?
U3 12.03 5.06 .00
U10 5.11 1.38 2.63

I can turn on Power Supply by jumping PS-0n with 1kohm jumper to 5vdc
Does anyone have a list of what LDO controls what functions? Thereis lots of info on checking the LDO. What is the proper sequence of checking them?
Replacing U7 will let the PS turn on? or U7 and U9?

[budm]

Re: Vizio LDO Voltage Reg VW42LHDTV10A

U7 3.32 1.11 .02 ---- Bad output and is the input voltage correct?, .02 +1.25Vref = 1.27V, so it is bad.
U9 3.32 1.51 .001---- Is the input voltage correct. 3.32V is enough input voltage for the LDO to operate. This one may be 1.5V fixed LDO. What is the number printed on the body?
I believe the output of U33 feeds the input of U7 and U9, you can trace that out.

[Ltank]

Re: Vizio LDO Voltage Reg VW42LHDTV10A

Well I replaces U7 a 1117 adjustable LDO and the set came to life. Set works fine I turned on/off several times and has played several hours. The mainboard wad not sending the PS-on to the SMPS. Set mow works after replacing U7. Nothing else was replaced so I assume U7 supplies the voltage for the PS-on command

[budm]

Re: Vizio LDO Voltage Reg VW42LHDTV10A

Glad to hear it working now.

[Derrick8265]

Re: FIXED...Vizio LDO Voltage Reg U7 VW42LHDTV10A

Bud -
You asked me to follow-up on my Vizio 42" regulator (U7) repair:..

A few weeks ago, you helped me identify the correct voltages for my Main-Board Regulators in my VW42LHDTV10A. You posted the links to the Digi-Key Regulators I needed, mainly U7. I ordered them and replaced U7 only...and IT POWERED ON IMMEDIATELY! So, Thank you for your help!

I can not find in this forum where I was posting before, so I followed up here since this thread is about the same problem and solution.

My symptoms were logo glows orange, but nothing else is responsive.
We tried replacing the PSU first (before joining this site), but that produced no changes. So, now I have a good spare PSU sitting around in a box. Oh well, at least the regs were cheap!

In the end, it only cost about .45 cents to repair a TV that I intercepted on its way to the dump. I learned a bunch from this experience, and am now prepared for other regs that might go bad too, because I ordered U33, U2, U9, U8, etc...when I was placing the order.

Thanks again!