Vizio VX42L Progress?

[chummyb]

Re: Vizio VX42L Progress?

Thanks for all the great info and leads. This has been (albeit frustrating at times) a great experience and learning opportunity for me. The supply store here in town only carried the caps, so I have replaced the filter cap that feeds the U2 regulator. I ordered 5 new 1117 regulators from digikey and will keep everyone posted on the outcome of the project!

[chummyb]

Re: Vizio VX42L Progress?

You guys were spot on with identifying the U2 reg as the culprit. I replaced both the regulator and the filter cap that fed the reg and the TV works perfectly! I cant thank everyone enough for the help and education! I have 4 left over 1117 adjustable regs if anyone needs them for their Vizio project. Shoot me a PM and I will gladly send them to you. It's the least I can do for others troubleshooting away here.

[tom66]

Re: Vizio VX42L Progress?

Congratulations on fixing them. I still do not know what leads to the regulators failing. I have encountered failed regulators in two products, one Samsung T-con and one Haier/Bush LCD TV, but Vizios seem to be littered with them...

[retiredcaps]

Re: Vizio VX42L Progress?

I have 4 left over 1117 adjustable regs if anyone needs them for their Vizio project.

Keep them. The 1117 might fail again in the Vizios. Just after your post or around the same time, I took time to write a "guide" for measuring voltage regulators. It is a common problem with Vizio so I figured I would save us time if we had a FAQ.

[tt_tony]

Re: Vizio VX42L Progress?

Hi, ive got the same TV, same problem. U33 voltage was incorrect. I may have complicated things a bit though. I hate to write this because i know it was a bonehead move. I didnt have the patience to wait for the new part to see if it would fix the problem so I soldered in a jumper from the 3.3v output on U8 to the same pin on U33. The TV worked for a short while, then shut off. I figured I just damaged U8 also. But when I soldered in all new regs it still does the same thing. All of the regulator voltages discussed in this thread seem to be correct according to what ive read here. Can someone point me to a likely culprit (besides myself) and how to check it? thx.

[tt_tony]

Re: Vizio VX42L Progress?

Btw, if it wasn't clear in the previous post, the Vizio logo will be orange when the tv is plugged in and will turn white when the power button is pressed. after about 5 seconds it will go back to orange. the screen stays black.

[tt_tony]

Re: Vizio VX42L Progress?

ok, I have made some progress. I was going through budm's LCD diagnostic guide and when I removed the cover for the TCON board and pressed the power button the TV came on. i installed the screws that hold the board down without the cover and it is still working. I don't have pictures of the board handy but when I check voltage from chassis ground to the board ground where the screws attach, it is ZERO, obviously. But there are two other points on the board where the cover touches the board ground. I checked for voltage from chassis ground to these points and there is about 5 millivolts. I put some electrical tape between the board and the cover to make sure these points don't make contact (there was some insulating material there already) and this had no effect.

[tt_tony]

Re: Vizio VX42L Progress?

what the heck??

nobody loves me.

BTW, I have been using the TV for a few days now, still working perfectly. T-Con has cover removed.

[suriips450]

Re: Vizio VX42L Progress?

You guys were spot on with identifying the U2 reg as the culprit. I replaced both the regulator and the filter cap that fed the reg and the TV works perfectly! I cant thank everyone enough for the help and education! I have 4 left over 1117 adjustable regs if anyone needs them for their Vizio project. Shoot me a PM and I will gladly send them to you. It's the least I can do for others troubleshooting away here.

Hi ya, please could you let me know part number for 1117 adj reg that you bought?

Thanks

[rboyer]

Re: Vizio VX42L Progress?

I have one of these which I just recently acquired and put up on the bench yesterday. It's funny because i've repaired enough Vizio tvs that i'm in the habit of going straight to the voltage regulators on the mainboard as soon as I get one open and inspect for visible damage. Turns out I missed one very important thing last night. My mainboard was getting 5 volts and all of my regulators were working properly but I neglected to check my power board for my other voltages until later. Turns out it wasn't putting out 12 or 24 volts! I had IC601 blown out on the bottom of the board! I'm only mentioning this because sometimes it's easy to not cover all of your bases. When I see a broken Vizio I think "Easy fix, 90 percent seem to be $2 in regulators" but that's not always the case with electronics and I should have seen that before wasting a couple of hours working ahead of myself. I'm hoping that when I get time later today I can root though my "repository" of broken tv parts and atleast find a similar power supply to test with. For how cheap a good working used supply costs for these tvs now it's actually worth just buying one and throwing it in.