Voire LCD19VH65 Schematic

[1beertap]

I have a backlight but no picture or sound. I have ordered another main board but would like to fix original board. Any ideas where to find a schematic for this LCD TV?

[rmoody]

Re: Voire LCD19VH65 Schematic

From my short lived tv repair experience, my problem when getting backlight but no picture has ended up being the Tcon and not the main board. It could be either though. Maybe you could explain more about the problem and give us some pics. A good check would be to check the fuses on the Tcon board. Usually labeled F1 and F2 if a second is available.

[PlainBill]

Re: Voire LCD19VH65 Schematic

I have a backlight but no picture or sound. I have ordered another main board but would like to fix original board. Any ideas where to find a schematic for this LCD TV?

Viore is one of those many brands whose service information is not available. Even the 'rip off' paid manual sites don't claim to have it. In general all we can do is check for obvious problems - bulging caps, bad voltage regulators, etc.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

This unit doesn't have a separate tcon board. It only has one board. F101 fuse test good. Since I am assuming that most built-in DVD players on TVs require 12vdc and 5vdc to work, the unit has 5vdc going to the built-in DVD player, but it doesn't have 12vdc. Also, I don't have a schematic so I can't verify.

[1beertap]

Re: Voire LCD19VH65 Schematic

Well, I replaced the main board with another that I received today and still have same problem. I did notice a brief sound, like a capacitor charging up, coming from speakers upon turning unit on but nothing else. The back light works and red light turns green in front when the unit is on. Also, I noticed two red pixels stuck on. I may have picture but not the one I want. Any ideas? I can post photos if it would help.

[1beertap]

Re: Voire LCD19VH65 Schematic

The TV has standby power and comes on with backlight but no picture, sound or response from menu buttons. If Tcon board is disconnected should I get audio?

[PlainBill]

Re: Voire LCD19VH65 Schematic

1. Pictures help - a lot.

2. If the power supply and the input and audio sections of the main board work, and you are feeding in a signal with audio, and the volume is high enoung, and is not muted, then yes, you should hear the audio signal from the speakers.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

Attached are some pictures. I replaced the Main/Power/Inverter board with another one and got the same results. I felt that I could have gotten a bad board so I requested another via RMA. When the new board arrives and I install it then still get same result I am totally going to suspect the TCON board since it is the only other board besides the menu switch/button board.

[PlainBill]

Re: Voire LCD19VH65 Schematic

The pictures clear up a lot of confusion about what you were discussing. The obvious one - the main board IS the main board - power supply, inverter, signal input, audio all rolled into one.

One point that you are probably already aware of; this panel does not have a TCON in the usual sense. There is a panel board integrated into it that serves the same function.

I've marked up one of the pictures to point out a few items to be investigated..

The yellow circles indicate what I believe are several LDO regulators. These would have the output voltage included in the part number. You should check the output voltage on them.

The device circled in orange may be a bucking regulator, or it may be something else.

There may be several more LDO regulators near the power supply section; none of the pictures showed the area clearly enough that I could be certain.

The connector circled in white is the LVDS connector. If that is disconnected from the board, the LCD panel and panel board are taken out of the picture.

It is rare, but not unheard of for a button board to cause problems. By measuring voltages on the lines to the board as buttons are pressed you should be able to identify a problem.

EDIT: Two more LDO regulators (1117 type) identified and circled on the second picture.

Re-edit. There is some history of common problems with LDO regulators. One certain Vizio main board often has a defective U33 - a 3.3V regulator. Symptoms are similar.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

I re-edited the photos to show my findings. (AZ1084S-ADJE1) I couldn't find a voltage value for this one. It's not in the part number.

Also, button board voltages change accordingly when the buttons are pressed. Three wires, in total, going to buttons. Ground test good to chassis and the other two wires have 3.29v on each with no button pressed. When buttons are pressed in order, voltage drops respectively at 2.42v, 0.87v, and 0v, then the next three are the same for a total of six buttons.

[PlainBill]

Re: Voire LCD19VH65 Schematic

I re-edited the photos to show my findings. (AZ1084S-ADJE1) I couldn't find a voltage value for this one. It's not in the part number.

Also, button board voltages change accordingly when the buttons are pressed. Three wires, in total, going to buttons. Ground test good to chassis and the other two wires have 3.29v on each with no button pressed. When buttons are pressed in order, voltage drops respectively at 2.42v, 0.87v, and 0v, then the next three are the same for a total of six buttons.

It IS in the part number -ADJ. The key to those is the output voltage should be 1.25V above the Adj input, and it is. So it looks like all the regulators are operating properly.

Good work on the button board, and I note the 'mystery part' is the audio amp.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

I have just replaced the main/power/inverter board for a third time with no luck. I have tested the LVDS cable to be good. I think the problem can only be on the panel board. please advise?

[1beertap]

Re: Voire LCD19VH65 Schematic

If I unplug the LVDS cable while the tv is on and rock the connector in and out, I should get a response from the screen?

[PlainBill]

Re: Voire LCD19VH65 Schematic

If I unplug the LVDS cable while the tv is on and rock the connector in and out, I should get a response from the screen?

I don'tknow, that sounds like a very bad thing to do. The power for the panel runs through the LVDS cable.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

PlainBill, the only reason I ask is because you posted a link to another person (http://www.scribd.com/doc/25276757/E...g-10-22-09-OPT) and it applies to Sony but I tried it to test for a response on the screen. I got the response just as the document said. My next question is should I have sound with the LVDS cable unplugged? The tv stays on with green light but I am unable to get any response from any button other than power and of course no sound. Sometimes, when I turn it on I hear a short sound like a "fart" or realistically a capacitor discharging/charging up coming from the speakers. Since I can't control the volume I'm thinking the volume may be turned down and I can't access it from the buttons. Thanks.

[PlainBill]

Re: Voire LCD19VH65 Schematic

PlainBill, the only reason I ask is because you posted a link to another person (http://www.scribd.com/doc/25276757/E...g-10-22-09-OPT) and it applies to Sony but I tried it to test for a response on the screen. I got the response just as the document said. My next question is should I have sound with the LVDS cable unplugged? The tv stays on with green light but I am unable to get any response from any button other than power and of course no sound. Sometimes, when I turn it on I hear a short sound like a "fart" or realistically a capacitor discharging/charging up coming from the speakers. Since I can't control the volume I'm thinking the volume may be turned down and I can't access it from the buttons. Thanks.

The following is NOT a well established guide, verified by numerous tests, it has been verified on only one or two TVs. In general, if the main board is working, you should be able to get sound even though the LVDS cable is not connected. Of course, this assumes you have a sound source attached to an input, and can select various sources by an input button.

The 'gotcha' to the above is I know enough electronics to realize it would be POSSIBLE to design a main board that would shut down the sound if the LVDS was not connected to a tcon. I can't think of any reason to do so, except to make troubleshooting more difficult, but that doesn't mean I know everything.

PlainBill

[1beertap]

Re: Voire LCD19VH65 Schematic

Does anyone have a broken screen for this tv? I really just need the panel board attached to it in order to swap components for repair.

[1beertap]

Re: Voire LCD19VH65 Schematic

I found another panel board and now, the tv works.

[Argonto]

Re: Voire LCD19VH65 Schematic

so you replaced the tcon/panel board? And that made it work? I ask because i may have a similar issue...

Thanks

[tw2005]

Re: Voire LCD19VH65 Schematic

I found another panel board and now, the tv works.

You can add me to the list for wanting to know what exactly you did to fix this. I have a 22" LCD which I recently went through the same deal.

I quickly came to the conclusion mine was a panel issue once I had replaced the main board, psu, etc all at once and ended up with the same deal.

That board is part of the panel so I can't see how it could be replaced except if you got lucky working out which part on the board is faulty.

The fuse on my board is blown and I noticed with a higher value fuse the 5V line is down to 0.6v with fuse getting warm.

Seems to me I have a shorted component.

Interested to find out what you found with yours and what part you replaced.