Sharp Aquos LC-42D62U Display Output Problem

[trusean]

Hello, my TV display output is not working right. I have multiple horizontal and vertical lines running throughout the display, similar to the infamous scene in the movie The Matrix. The lines are symmetrical, like graph paper. Varying in colours. I have had it diagnosed at the repair shop but I want more opinions. His diagnosis was that the mainboard needed to be replaced. The cost: $400 plus labour. What a joke. Well indeed the price for a mainboard on this particular model is listed as upwards of $400, I have one on its way for $74 all in. I have already disassembled the TV and removed the mainboard. So all I have to do is wait. So why am I posting?

Well I had another technician look at the TV with a different result. Unfortunately, he didn't speak English well and was reluctant to verify the exact part number the TV needed (maybe he didn't want me to figure out he was going to burn me for $600 minus the $100 part he was going to buy offline). Anyways, I was able to make out a little of what he said. He attributed the problem to the power supply. Now I have examined the psu, no bad caps from first examination.

So my question is, does anyone have any input? I don't understand why the psu could be the issue if the TV has no problem getting power, lighting all lamps and turning on and off. Perhaps the mainboard isn't getting enough power due to the failure on the psu. Regardless, I am willing to install the new mainboard and if this is unsuccessful, I will order a psu aprrox. the same price.

Finally, I have also read about the tcon board also causing these similar issues. Any input would be appreciated. Sorry for the long post and I have images if needed.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Pics. Thanks again.

[retiredcaps]

Re: Sharp Aquos LC-42D62U Display Output Problem

I have multiple horizontal and vertical lines running throughout the display, similar to the infamous scene in the movie The Matrix.

Finally, I have also read about the tcon board also causing these similar issues.

When you press the menu button, do the above lines show up?

edit: Ignore the above question. Pics were not posted when I asked the question.

edit2: See my friend's LG thread ...

https://www.badcaps.net/forum/showthread.php?p=135952

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Yes they do. When the menu goes away the lines remain.

[Hobby 1]

Re: Sharp Aquos LC-42D62U Display Output Problem

I've seen this before and fixed it. Its the main board with the input connectors on the side plate. Its not the power supply board.

[Hobby 1]

Re: Sharp Aquos LC-42D62U Display Output Problem

It is also not the T-con board. The set I worked on, the owner was sold a t-con board by another tech who said that would fix it. It didn't. This problem also shows up on other older Sharp models. Fixed 3 so far.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

I've seen this before and fixed it. Its the main board with the input connectors on the side plate. Its not the power supply board.

So I'm assuming that I will require a new main board from what you have experianced. Will I also need the cables to connect the two inputs (psu to main board)? Or is it just the input harness that is sodered to the board?

Also, if the main board isn't the problem, could it perhaps the input harness located on the psu that is causing the issue?

Thanks again.

[Hobby 1]

Re: Sharp Aquos LC-42D62U Display Output Problem

Just the main board. The cables should be fine to re-use. I have all the parts from one of these sets that had a broken screen, if you need it and if its allowed to sell on this site.

[PlainBill]

Re: Sharp Aquos LC-42D62U Display Output Problem

Just the main board. The cables should be fine to re-use. I have all the parts from one of these sets that had a broken screen, if you need it and if its allowed to sell on this site.

https://www.badcaps.net/forum/forumdisplay.php?f=12

PlainBill

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

So I installed my new main board. Turned on the TV, and it fixed the display problem. As soon as the TV turns on, the screen goes to white with no lines that were previously there. However, the TV turned off, and now will not turn back on. So I know that the new main board fixed my orginal problem. But now my TV won't turn on. The green LED light in the front is flashing. I don't want to have to buy a new psu. Is there any suggestions? Like a sequence to return to factory defualts, or new firmware? Thanks.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

bump, anyone?

[Hobby 1]

Re: Sharp Aquos LC-42D62U Display Output Problem

The LED flashing is an error code. Which LED, power or another one or both and how many flashes....
There is a reset procedure in the service manual.....
Are the voltages still good? especially the backlight voltage.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

More to add: I was able to get the TV to turn by holding down the "Vol -" and "Input" buttons at the same time and plugging in the set as described in a post to get into the factory settings. Again, the relay turns, a black screen which fades to a white screen, and then faliure, the TV turns off. And I am unable to access the settings menus. I can do this many times. Any ideas on why my TV would work fine (of course without the display issue mentioned about) prior to installing a new, factory made main board, but now will not even turn on after installing the new part? I just doesn't make sense that a new part would cause an entirly new problem. The only explanation I can muster is that the TV is confused and needs to be returned to factory defaults as there is a new piece of hardware installed, similar to installing a new piece of hardware in my computer.

Thanks.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

With, respect to the LED flasing, The green LED power light is flashing consitantly once evey second. No OPC light. Which suggests inverter board?

[Hobby 1]

Re: Sharp Aquos LC-42D62U Display Output Problem

Well, it can suggest an inverter problem but it can also suggest that the inverter board is not getting the right voltage. Put the original board back and see if you can get to the original problem. Was this an ebay bought board? Lots of defective ones sold there...
I have replaced many Sharp boards and they don't come up with new problems unless the replacement board is defective to begin with. A white or grey screen suggests no signal to the T-con board...

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Well, it can suggest an inverter problem but it can also suggest that the inverter board is not getting the right voltage. Put the original board back and see if you can get to the original problem. Was this an ebay bought board? Lots of defective ones sold there...
I have replaced many Sharp boards and they don't come up with new problems unless the replacement board is defective to begin with. A white or grey screen suggests no signal to the T-con board...

Thanks for the info btw. I did put the board back in last night and guess what, same original problem, which is good. The "new" board was indeed bought from ebay. It wasn't a personal sale however, it was a store ebay account. There is an exchange policy, but I think only seven days.

Just to confirm, the T-con board is located under all the metal structure plates, a the top of the TV, with a red/orange coloured thin ribbon cable connecting to the main board?

Do you think, now that the TV won't even turn on, a new power supply could rectify either issues? My theory is that with my old main board, something happened with a voltage spike or something which fried the main board to the state its in now along with causing damage to the psu it self. Now with a new main board, the corrupt psu is not able to power enough to produce a picture? Just a thought, as the TV can turn on fine with my old main but not even able to power on with a new one. BTW I have examined the new board I bought and there seems to be no apperent signs of failure, to the naked eye that is.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Just for fun I thought I would throw up some more pics. The first one is the two main boards. I took close up shots to show that even though they are the same model number, they have different assemblies.

The other pics are the psu. Just wanted to show that all the caps seem perfect. I really don't know whats going on here.

I have a faulty main board, as told by even a pain tech. so I get a new one. Plug the bugger in, now the TV won't turn one?! WTF. These things are so temperamental. You'd think a display problem such as mine could be solved simply by a plug and play method. Arg!

[crepiduse]

Re: Sharp Aquos LC-42D62U Display Output Problem

Those two main boards are not the same, one has one version and the other another. One is a W1 and the other is a W3. Wont work.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Those two main boards are not the same, one has one version and the other another. One is a W1 and the other is a W3. Wont work.

You are correct, but mine is a W5, not 3 (I know, in the pic it does look like a 3). Regardless, thank you for pointing out that small, but very important observation! You rock. Now I'm sure I am out $74 as I'm sure they won't refund my money because their model, which is the same as mine, is different than mine, if that makes any sense. I guess I will try and send a nice email explaning the situation. Thanks again.

[trusean]

Re: Sharp Aquos LC-42D62U Display Output Problem

Those two main boards are not the same, one has one version and the other another. One is a W1 and the other is a W3. Wont work.

Sorry again, by any chance would you know the differences between the two? Or the what the "Wx" repersents? It might be good for me to know to support my case when emailing the store.