Vizio L42HDTV10A Won't Turn On

[barkster]

Neighbor threw away a Vizio L42HDTV10A and it looks like in good condition but it doesn't show any signs of life. When plug in it doesn't do anything, no lights or anything when press power button. I took apart and the power supply at first glance looks good, don't see any bulging caps. I've read so some of the testing procedures but I'm not sure how to test this power supply. How can I check it to make sure it is the culprit. I have a capacity meter but I'm not sure if you can test in-circuit or not because when I do the numbers aren't close at all so I assume that is why. Can someone tell me how to test this. I'm assuming one of the voltage regulators is out. Here are the pics.

[selldoor]

Re: Vizio L42HDTV10A Won't Turn On

Hi - I dont know much about TVs but starter question would be as well as a cap tester
do you have a multimeter. If so have you tested the fuse for continuity?
Also in Pic 3 the inductor (copper coil) far left - is it as burnt as it looks?
or is it just shadow.

[budm]

Re: Vizio L42HDTV10A Won't Turn On

Check the main AC fuse to make sure it is OK first. Put the probes of DC volt meter to the 5VSTBY pin and GND pin of the connector to see if you do have 5V Standby voltage or not.

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

I never noticed that as being burnt but I'll confirm. Yes fuse is good and I just found some REALLY great videos on net from a guy that shows how to test just about every regulator, fuse, etc on the power supply and main board. I will let you know results tonight. Thanks

[budm]

Re: Vizio L42HDTV10A Won't Turn On

The main key is that you have to have at least the 5VSTBY working first.

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

Ok, getting 5v out of power supply and it looks like fuse F2 is blown, only getting 5v on one side. I'll order another fuse and I'm going to order a couple of each of the voltage regulators on the motherboard as well while I'm at it. Should I be worried that it it blown? Something I assume caused it but I guess don't know if it from surge or something wrong on motherboard. The TV looks brand new and I don't see any bulging caps or any hot spots on any of the boards. Any advice would be grateful, thanks

[budm]

Re: Vizio L42HDTV10A Won't Turn On

What is the fuse rating?
Put meter in Ohm mode then take the resistance reading on the end of the fuse that is not showing 5V, we need to know if that side of the fuse has shorted circuit to ground or not.

[selldoor]

Re: Vizio L42HDTV10A Won't Turn On

Did you get to look at the inductor.

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

I didn't think about that I just put it in diode mode and check it and didn't get anything. I'll check to see if it is grounded tonight.

Selldoor, sorry, yes I did check it and it is paint/ink

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

Ok, I checked both sides of each fuse and don't seem to be grounded but I did have question. When I had it on ohm's it did show ohm readings on all 4 sides but when on continuity it did not show any short on any sides. How should I be properly checking for this being grounded? Also, if they are not grounded should I just replace and see if it works? What would be my next step? Thanks

[budm]

Re: Vizio L42HDTV10A Won't Turn On

If show anything less than 50 Ohms or so I would worry about it, if it shows in K ohms range, it may be OK since the circuits that have problem may be after the voltage regulators.
You can try a new fuse for now. I fixed some of these Vizio that had blown fuse for reason that I do not know, I checked the current draw and it does not show any thing bad, put new fuse in and it still working.
http://s807.photobucket.com/user/bud...?sort=3&page=1

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

thanks budm I'll order a few extras and see what happens, if it powers on I'll measure the current. I'm also going to check diodes, rectifiers around it also. I'll order today and will get parts tomorrow, mouser isn't far from me so I should know something this weekend.

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

Success, replace the SMD fuse and it turned on. I left it on for over an hour and still good. Hopefully that will fix it for good, one tv saved from garbage and only cost me $1.06 to fix. Thanks for all the help. Next is an hannspree lcd monitor.

[budm]

Re: Vizio L42HDTV10A Won't Turn On

Glad to hear it is working. Hanspree 281?

[barkster]

Re: Vizio L42HDTV10A Won't Turn On

No it's a HF237HPB, turns on and then off but I don't think it is the power supply. I checked the the ohms on the cfl inductors and they were pretty close like 440 and 449. The image seems dim at first so I think one of the bulbs may be cracked or shorted??

[stefanolivi]

Re: Vizio L42HDTV10A Won't Turn On

Hi everyone! This is my first post, so please bear with me if I do not follow all etiquette rules (even though I will try).

I have a non-functional Vizio L42HDTV10A, which stubbornly refuses to turn on. I followed the excellent advises of BudM and following links:
https://www.youtube.com/watch?v=jR2UZhoDC2c
https://www.youtube.com/watch?v=y9gmAxRXyT0
and was able to determine that:
1) 5V standby is present
2) No PSON voltage
3) Applying 5V on PSON does force the power supply board relays to click
4) Voltages on the side buttons connector do change when switches are pressed, with the exception of the power on button. Nothing happens while pressing this connector
5) After disconnecting the side button mini-board, the connector for power on seems defective: ~45kOhm non matter if pressed or not
6) After reconnecting the mini-board, creating a short on the connector by wires still does not turn the TV on.
7) I was able to locate three fuses: one on the power supply board, and two SMD on the logic board. All check properly.

I gather that I might have had a faulty power on connector, but how do I proceed from here?

Any help will be greatly appreciated

[stefanolivi]

Re: Vizio L42HDTV10A Won't Turn On

Refreshing the message, in case someone might have missed it during the migration process.

[laself]

Re: Vizio L42HDTV10A Won't Turn On

I'm new here as well because I have a Vizio VW42L that was turning off on its own for a few months then simply would not stay on. So I found this forum looking for answers.

Reading a lot of the posts I looked into the tv and found bad capacitors on the primary inverter board. (Pretty sure thats the correct term for the board) Anyway I thought I luckily found the obvious problem. I got same rated caps and replaced the bad ones. Now I get NOTHING when turning on the tv. No orange light, white light, nothing. I was careful handling and soldering and have double checked the polarity and the 4 connections. (2 ribbon and 2 plastic connector)

I'm hoping you guys with experience can tell me something obvious I messed up. I dont have the skill nor equipment to replace tiny components and would have to replace the board.