Sharp LC-52SB55U Power Opc Blinking

[MazdaSpeed6]

I picked up a 52" Sharp LCD TV that has what I think is a power supply issue.

I am not a total noob but I haven't repaired a TV before. I have repaired XBOX's, XBOX 360's, Spa packs and other smaller items. I can solder fine but I am not sure what the problem is or where to look first.

So when I plug the TV in a relay clicks on and the power light comes on, shortly after another relay clicks(maybe the same one) and the Power and OPC light blink twice then the OPC blinks 3 more times and it just repeats that until I hit the power then it starts over.

I have tried a few reset techniques like holding the power and plugging in with no change. The TV is apart and I skimmed over everything and it doesn't look like anything is fried or bulging.

From what I have read it is probably the power supply, I'm hoping I can just replace some caps, relays or something instead of more expensive parts. I will post some pics shortly.

Thanks in advance!

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Here are the pictures if there is a better way to post them let me know.

Board model
http://img837.*************/i/imag0328x.jpg/

Full bottom
http://img850.*************/i/imag0323.jpg/

1/2 bottom
http://img232.*************/i/imag0324y.jpg/

Other 1/2 Bottom
http://img153.*************/i/imag0325b.jpg/

Full top
http://img35.*************/i/imag0329x.jpg/

1/2 top
http://img268.*************/i/imag0326.jpg/

Other 1/2 top
http://img849.*************/i/imag0327.jpg/

[retiredcaps]

Re: Sharp LC-52SB55U Power Opc Blinking

if there is a better way to post them let me know.

Yes, there is a better way to post pictures. Upload your pictures using the manage attachment function. Pics can be 2000x2000 or lower resolution.

See the reasons WHY at

https://www.badcaps.net/forum/showpo...5&postcount=12

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

For some reason I can't edit now. If a mod would like to delete that post I can re-post the pics the correct way. I apologize for that.

[retiredcaps]

Re: Sharp LC-52SB55U Power Opc Blinking

For some reason I can't edit now.

The time limit to edit old threads is 30 minutes after it has been posted.

Just attach the pics in this thread (please do not post inline).

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

I just found a Service manual and this is my error. Any ideas what I could look at for the no power for 5V? I will look more indepth on the board and try to find pin 33.

Pics of power board posted here.


Power failure details (Power LED flashes twice and OPC LED flashes)

DET_5V failure
Flashes 3 times
DET_5V (pin 33) failure (L). 5V is not applied.
If error is detected during operation, error standby is activated
by polling.

[rayrod81]

Re: Sharp LC-52SB55U Power Opc Blinking

After looking through the service manual I would say it is either the main board or power supply. The 5V detect is handled on the main board. Either there is no 5V coming off the power supply or there is a bad component on the main board that is overloading the 5V and causing the tv to go into protect. If there are no shorted or otherwise bad components on the power supply then it is a bad main board. I suspect a bad main board rather than a bad power supply due to the fact that the main board seemed to be a problem in some Sharp TVs.

[retiredcaps]

Re: Sharp LC-52SB55U Power Opc Blinking

If you have a multimeter, measure and report some of the voltages at the connectors. Your photos are blurry and we can't make out the legend at the connectors.

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Alright I'll try to test tonight. I will also put up better pics of the connectors.

Thanks

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Sorry to keep posting. I was looking through the service manual again and it has an option for the power blinking twice and the opc blink 1-8 times the opc flashes a total of 5 so is the error power blinks twice and opc blinks 5 times? or is it power blinks twice opc blinks 3 times?

If it is 5 times the error is

PNL_12V failure
Flashes 5 times

DET_PNL_12V (pin 35) failure (L). Panel power is not applied.
If error is detected during operation, error standby is activated
by polling.

[rayrod81]

Re: Sharp LC-52SB55U Power Opc Blinking

I should have read it better before I replied. It is the 12V detect that is bad. I had a 42" with the same problem. It was a bad LCD Control Card. To test if that is the problem unplug the three cables from the LCD Controller and turn it on. If it is like the model I had it should turn on without going into protect. There will be no image on the screen but the backlights should turn on.

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

I should have read it better before I replied. It is the 12V detect that is bad. I had a 42" with the same problem. It was a bad LCD Control Card. To test if that is the problem unplug the three cables from the LCD Controller and turn it on. If it is like the model I had it should turn on without going into protect. There will be no image on the screen but the backlights should turn on.

I will try that tonight.

I tested the voltage in the PNL 12v and it is like .4 or so....?

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Here are some pics of the plus on the PSU. I am guessing caps could cause the no power what else should I look at?

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Anyone....?

[rayrod81]

Re: Sharp LC-52SB55U Power Opc Blinking

A couple questions. First, did you measure the voltage with tv on or right at power up? Second, was the cable for the panel 12v disconnected or not? The reason I ask is that if the problem is with the LCD Controller you will have to disconnect that to get the voltage to come up. Otherwise the voltage will be close to 0 volts like you measured. You will not be able to get a good reading for the voltage when the TV is off or after it is in protect. That means you will have to measure voltage right as you hit the power button and before it shuts down in protect mode.

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

I measured it with the cable disconnected and right after power up before protect mode. It is 0 off and 0 in protect.

[rayrod81]

Re: Sharp LC-52SB55U Power Opc Blinking

At that point I would suspect the power supply. Have you found any shorted or otherwise questionable components on the power supply?

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Not really. I can get all the boards on ebay for like $250 or just the power supply for around $60. The person I got it from said it stopped working while they were out of town and there may have been a power outage/lighting.

I would really like to fix it without replacing boards if possible. Any ides on what to look at or test mosfets or something?

The caps look fine but I could take them out and test them or replace them if needed they aren't to expensive.

Thanks for the help!

[rayrod81]

Re: Sharp LC-52SB55U Power Opc Blinking

It is hard to say without having the board in hand. I would start by checking the voltage regulators attached to the heat sink near the connectors. Then you would want to check any diodes and transistors on the 12V circuit (there look to be quite a few SMDs on the back of the power supply).

[MazdaSpeed6]

Re: Sharp LC-52SB55U Power Opc Blinking

Quite a few indeed! i put an offer on a power supply we'll see what happens with that. I may just order one and hope for the best. If there is some more in site or experience with this TV that would be great.

Thanks for all the help rayrod. I will look at what you suggested as best I can.