sharp aquos lc52d64u no display or sound

[mxsteve751]

When turning on the tv no display or sound. Opc light blinks every other time that the power light blinks. Can hear the relay on power supply board click on then right back off. Doing volume up and channel down button hold relay clicks on but still no display and power light stays solid. No noticible blown capacitors or cold solder joints seen. The 12vDc and 60vdc at the inverter module 3 way connector is not there but if i disconnect that connector and power on the tv those voltages are present at the power supply board and a red led light blinks on the main board. Upon pluging either or both of the inverter connectors back in i loose the needed voltages and the relay clicks back off.

Any help would be appreciated thanks

[tom66]

Re: sharp aquos lc52d64u no display or sound

Can you check the 60V and 12V pins for shorts? Red probe on 60V or 12V, black probe on chassis ground.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

Ok will do when i get home. Cant believe i didnt think of that yet

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

yes there does appear to be a short to ground on the 60v pin of the inverter board but only when being supplied ground through either the 3 way connector from the power supply of the connector from the main board. measurments the same on the left and right boards

[tom66]

Re: sharp aquos lc52d64u no display or sound

From what I know of these Sharp TVs they use the 60V to power the backlight inverter, to light the screen up. The inverter is composed of some MOSFETs. Have you checked all the MOSFETs? If you need help here, you will need to post some pictures of your boards.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

so most certainly that 60v should not be going to ground? correct? i have went as far as remove the board and have it seperate from the tv and check resistance of the ground to the 60v and there is no resistance there. if that is a sure sign the inverter is bad ( in which case both inverters are bad) then perhaps i need to purchase some new inverters. my main concern is that the problem is worth fixing and not going to be something like an lcd panel or back light

[tom66]

Re: sharp aquos lc52d64u no display or sound

Yes, it should not be shorted (<10 ohms.)

You are testing when the power is off, right?

It is unlikely to be an LCD panel/backlight fault if the TV just stopped working one day and the 60V has a short.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

I tested with the power off and i have also tested with the board seperate with nothing connected to it by doing resistance test black lead on ground pin of 3 way connector from power supply connection and red lead on 60v

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

so theres around 6 mosfets on each board (left and right side boards) each mosfet has 3 pins coming out that go to the circuit board. i measured the resistance of each pin on each mosfet to ground. 4 of the 6 on each board has continuity to ground on one pin each. 2 of the 6 has continuity to ground on all 3 pins. im thinking that solves the problem , 4 bad mosfets total

[tom66]

Re: sharp aquos lc52d64u no display or sound

Actually, it is the two that show continuity between all three pins that are bad, because this indicates that they are completely shorted, whereas the others are likely only being influenced by the short on the 60V rail.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

Right i said for because theres 2 on each board with conyinuity on all 3 pins

[tom66]

Re: sharp aquos lc52d64u no display or sound

Best to remove them from circuit and see if they are still shorted out of circuit.

[tom66]

Re: sharp aquos lc52d64u no display or sound

OK, on the board you may have a part # which looks like

DUNTK
RUNTK

or similar.

I might be able to get you a schematic of it.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

Yes i removes the mosfets i thought were bad and yes they are no good as there is conituity between all 3 pins. I think i will most likely get those 2 boards off of ebay

[jjakatw]

Re: sharp aquos lc52d64u no display or sound

Good evening, I have a similiar issue with my LC42D43U-42. We changed the backlight inverter which did not correct the issue, but we think it may have been bad, we bought it off of ebay. Today we just installed a new main and terminal board, but found out we need to upload the software, which we can not find anywhere online. We also now get a solid green power light and opc stays steady and then goes out and then comes back on. Prior to this the tv would come on no picture, with sound, but fade to gray/black. Any ideas? Do you think it could also be the backlight inverter mosfets? Help.

[mxsteve751]

Re: sharp aquos lc52d64u no display or sound

Well as far as my tv goes i have replaced 2 if the backlight inverters and the tv work great now

[tom66]

Re: sharp aquos lc52d64u no display or sound

Glad to hear, thanks for feedback.

[ifixitnh]

Re: sharp aquos lc52d64u no display or sound

I also have an LC-52D64U and I get a picture for about 2 seconds then backlight goes out and power and OPC light come on steady. If I leave it the set shuts off but if I hit power off then on it does the same thing. I replaced the power board (it was cheap) and same thing. I do get a high pitched whine from the #3 inverter, would you suspect that is the problem?

[TheBanndit]

Re: sharp aquos lc52d64u no display or sound

Can you check the 60V and 12V pins for shorts? Red probe on 60V or 12V, black probe on chassis ground.

Hello all.
While googling for answer to my Sharp LC52D64U problem, this thread was the closest so far and tom66 seems to be quite knowledgeable.

My LC52D64U will not power up at all. As soon as you plug it in you can hear the relay click on, then off. Pushing the power button and the relay clicks on, then off.

The power LED blinks 2 times and the OPC LED simultaneously blinks 3 times. Seems to be saying DET_6V failure if I interpret that correctly. But I don't know what that is or where to test to verify that.

However a tech had said the main board DUNTKE558FM01S needed to be replaced. I thought I'd want to verify that since DUNTKE558FM01S seems to be hard to find.

Since this thread discusses power I thought to check that also. There are no shorts, but no steady 12VDC or 60VDC power (since the relay cuts out right away) with or without the wires connected. I do see that the left (as viewed from the back with the service panel removed) supply connector does momentarily show the proper 12VDC/60VDC power when the relay is on, but the right connector does not show the 12/60 volts but rather shows 'random' volts, but I wonder if that is just because the relay is not on long enough for power to stabilize.

Is it possible that the DPS-304BP-1 Rev S8 RDENCA235WJQZ inverter board is the problem? I see no visible problems anywhere in the entire LC52D64U - no swollen caps nor burned resistors.

Anyone provide any advice on pinpointing the problem?

Thanks all. Enjoy your day!