Olevia 747-b11 power on, screen dark

[ilyaz]

I will attempt my first ever LCD TV repair. Wish me luck.

Picked up an Olevia 747-b11 LCD TV. When plugged it, I can see the blue power light in front and some green lights through holes in the back cover. Screen is dark.

I took off the back cover. The caps on the power board seem to be OK. At least those that I can see without taking anything else off.

There are two boards symmetrically on the right and left of the power board. I have not removed their steel covers yet, planning to do so. Is it likely that the problem is with bad caps on one of both of the boards? If I do not find any bad caps on either of those boards, what else could be wrong?

Thanks much!

[budm]

Re: Olevia 747-b11 power on, screen dark

Post good clear pictures of the boards first so we will know what we are dealing with.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

OK here's what I have now: a photo of the whole back, then the power board in the middle, showing a couple of caps that seem to be OK, then the left and right boards. I have not removed the covers from those yet since I need to first find someone to help me move the TV somewhere where I can lay it flat. Once I do that I can remove the covers and take more detailed photos. Thx

[tom66]

Re: Olevia 747-b11 power on, screen dark

OK, 1st check, the red and black wires going to this board
https://www.badcaps.net/forum/attach...7&d=1385761403

What voltage do you see on across any pair of the red and black wires? (only need to check one of each colour.)

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

OK, 1st check, the red and black wires going to this board
https://www.badcaps.net/forum/attach...7&d=1385761403

What voltage do you see on across any pair of the red and black wires? (only need to check one of each colour.)

It was a bit hard to get the voltmeter probes to touch the contacts, but I think I did it, and I got 0 on both sides.

[tom66]

Re: Olevia 747-b11 power on, screen dark

If it's easier you could touch the metal pins on the board just be careful not to short anything out.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

If it's easier you could touch the metal pins on the board just be careful not to short anything out.

OK, this did not go so well. I realized that last time I measured, I did not turn the TV on. Turned it on and tried to measure on the right board. Got a spark and now have a black spot on the pins (see photo). Does it mean this board is likely fried and I will need a new one?

After that disconnected and measured as I did the 1st time. Got a reading of about 36v on the right but only about 1.1v on the left.

[tom66]

Re: Olevia 747-b11 power on, screen dark

That's what I feared but it's not too bad. You just shorted it to ground (the case..) Unplug power for a minute and try again. The PSU would have gone into a protection mode, no damage should occur.

After you complete repair I'd clean up that spot with a bit of 99% isoprop alcohol l and a q-tip.

You should be getting readings around 24V so make sure your meter is on volt DC.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

But what did I do wrong when I tried to measure while connected? I thought I was supposed to touch one of the pins next to the red top and one of the pins next to the black bottom of the connector with probes of my voltmeter. Or do you think I accidentally touched the metal cover on the right side of the photo with the side of one of the probes?

[tom66]

Re: Olevia 747-b11 power on, screen dark

Yes, I suspect you did that. I feared that might happen, but it won't cause any long lasting damage. The mark is deposited carbon from the high current arc that occurred, a surface mark.

Instead, a better option may be to try to probe the pins as they meet the connector.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

OK looks like it's 24v on both sides

[budm]

Re: Olevia 747-b11 power on, screen dark

I believe this TV uses CMO inveter boards, so I would at least check the small black fuse and the regular SMD fuses on both inverter board. You need to remove the metal shields off the boards.
For example, see the picture.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

I believe this TV uses CMO inveter boards, so I would at least check the small black fuse and the regular SMD fuses on both inverter board. You need to remove the metal shields off the boards.
For example, see the picture.

Budm, where are those fuses on the photo? Are they the two white ones marked KOAC? Which one of the black parts is the fuse? Thx!

[budm]

Re: Olevia 747-b11 power on, screen dark

The picture I posted is for the example of what the fuses look like, you need to take good pictures of your inverter boards for me to see.

[D.T.]

Re: Olevia 747-b11 power on, screen dark

I'm going through something similar with a 242-S11.

I found 9 bulged caps on the power supply. Found the whole board on fleabay new and used. Found cap repair kit on Amazon too. Probably going to get the cap repair kit.

Mine has a FSP271-4F02 power supply, the one you have is different. But I saw it on fleabay. That number is located on the component side of my PS.

I found this vid that might help the OP...

http://youtu.be/ab5_fupl_aw

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

I found this vid that might help the OP...

http://youtu.be/ab5_fupl_aw

I am wondering if the fact that I am getting 24v to the side boards means that the power board is fine.

[ilyaz]

Re: Olevia 747-b11 power on, screen dark

The picture I posted is for the example of what the fuses look like, you need to take good pictures of your inverter boards for me to see.

Will do, as soon as I move the thing to where I can lay it flat

[budm]

Re: Olevia 747-b11 power on, screen dark

The inverter is getting the correct voltage to operate, it will need BL_ON signal and maybe the Dimming signal to turn on the backlights.

[Ltank]

Re: Olevia 747-b11 power on, screen dark

I never liked those types of sets. All the shielding makes it a pain to check voltages while in operation. Inverter and P.S. not too bad but the main board mounts to the shielding and that to the chasis. At least its the foil side up when taken apart but boards needs to insulated from chasis and shorting out.
Like your Computer Case. an old Coolermaster. I got one too! I use it at the shop, but it has noisy fans. You really notice it when you turn it off and the room gets quiet.

[D.T.]

Re: Olevia 747-b11 power on, screen dark

Olevia has support at Sears. That's where I got mine in 2007.

www.searspartsdirect.com

http://www.searspartsdirect.com/part...levision-Parts

seems to have some of the parts available for the big LCD TV's...

Power supply for mine at $100 bucks.

FYI