Sharp Aquos LC-60LE633U won't turn on, no lights

[pmontone]

Hi,

I've got a Sharp Aquos LC-60LE633U LCD TV that all of the sudden will not turn on anymore. The TV shows no lights or anything when it's plugged in and the power button won't do anything.

I've taken it apart and checked the fuses and the power cord and looked for any bad caps or burn marks but nothing. I have attached a picture of the power supply board.

Please, any help would be greatly appreciated.

[johnboy1313]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Do you have a meter? If so, check the voltage across one of the two large horizontal capacitors above where the power cord connects to the PSU. Put the black meter on one leg and the red on the other. It should read in the 160V-170V range. I've got the 52" version of that TV sitting on my bench with the back off and a bad HDMI IC. It has the exact same PSU in it. If you get to a point that you need any reference readings, PM me. I'm on this site frequently.

[ben7]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

^I'd also reccomend checking to see if there is any standby voltage coming from the PSU.

Could you get a close up pic of the connector in the upper right corner of your picture? Please include the text next to the connector too, that is probably telling us which pins are for what voltage.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

I measured the voltage across the two caps above the power plug and got almost nothing, they both measure about 0.262VAC across the legs of the caps.

Here's a close up of the power connector on the top corner of the board.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

For those please use volt DC range.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

OK, sorry about that thought that was still part of the AC circuit. I get 159VDC on those caps.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

What voltage do you see here? Red probe on marked point, black probe on the chassis.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Basically nothing .001 VDC. I was just checking that with my diode checkr on my meter and it looks as it may be bad. I get my meter to buzz on both directions of the diode.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Remove it to confirm, but you may have found the fault.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

My bad it looks like I was on the wrong point with the chassis wire, I took the board off the tv to test it and I went to the wrong spot when I took your measurement. I am getting 5.06VDC across that point and the diode.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

OK, along the connector from the power supply to main board, what do you see on each pin?

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Everything is dead except for pin 15, it has 5.06VDC on it.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Here is a better picture of the power supply connector.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

OK, the main board is getting 5V, but it is not doing anything. Time to look at main board, this is the board with video inputs on it. Please supply a picture of it.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Here is the main board.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Service manual available here


Can you provide a close shot around the connector from the power board on the main board?

I think the only option will be to replace the main board, detailed schematics not available unfortunately.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Wait sorry this is the wrong one let me upload the right connector

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

Here is the connector to the power board.

[tom66]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

I was hoping to see fuses, but I don't see any.

[pmontone]

Re: Sharp Aquos LC-60LE633U won't turn on, no lights

tom, the diode you had me measure earlier that had 5.06V on it; while I was checking it with my meter diode function it was acting wired and appeared to be the only one doing this; but this diode would buzz then on my meter display the voltage would creep up until it got over 2 volts and then would read OL. Do you think this could be causing a problem or more likely the main board?