Sharp Aquos LC -70LE640U no power

[tjmethod]

A relative dropped off this set in hopes that I could fix it. Apparently there was a power surge and this tv among other electronic components in the house "shorted out" or died all at the same time. The tv shows no power. I tried unplugging, holding the power button for at least 10 seconds plugging in hitting power and then unplugging then vol/channel down while plugging in and both did nothing. I then pulled the power supply checked the fuse with a dmm which zero'd out and beeped which gives me the idea the power supply board very well may be good. Nothing looked burnt or bulging and I couldn't figure out the supposed stamped numbers for the voltages where the socket for the wiring harness to the main board should read or exactly how to test it although there is activity. The pins are in pairs and I would have to look again but I think there's 8 or 10 pairs. If anyone else has any advise on how to further troubleshoot the board or check for other clues as to why there's no power, any suggestions would be appreciated- thanks

[dskall]

Re: Sharp Aquos LC -70LE640U no power

Are you getting any flashing light on front? You should have voltage on at least one pin on connector from power board to main board. service manual

[tjmethod]

Re: Sharp Aquos LC -70LE640U no power

I'm sorry I posted the wrong model in the title it is a Sharp Aquos LC-60LE600U. It has no sign of life at all- no blinking lights or anything.

Do you know how I can change the title to the correct one

[dskall]

Re: Sharp Aquos LC -70LE640U no power

Think you have to repost to change title. You said there is activity but no voltages. You need to ground black lead to chassis. Back probe each pin going to main board. Should be markings on the power board identifying each pin.Some good pictures of the boards would be helpful.

[tjmethod]

Re: Sharp Aquos LC -70LE640U no power

I did start a new thread and heres the link:

https://www.badcaps.net/forum/showthread.php?t=60015

After putting the power supply back in and power plugged in, I tried to get voltages with a multimeter with the plug from the main board disconnected. What I found was that I only got some readings from a few pins from the column on the left. The column of pins on the right (row of pins closest to the board) were all 0.00. I'm not sure how and what exactly the readings should be or if it's accurate to get a reading with the plug from the main board disconnected. Maybe you can tell something from the pictures.

[Mike Hutchison]

Re: Sharp Aquos LC -70LE640U no power

No Power Repair Zener diode
https://www.youtube.com/watch?v=qEsLtvmcR4U

[tjmethod]

Re: Sharp Aquos LC -70LE640U no power

Hi thanks I don't know how to identify the Zener diode but I did check all the ones on the board in diode mode but without removing them from the board. Between all of them there was a range from 300's to 600's with the pos side on the anode side and neg on the cathode side and reversing the probes gave me an l or 1 laft on the screen

[freakaftr8]

Re: Sharp Aquos LC -70LE640U no power

Hey man long time. Yes definitely mainboard related. You could try to jumper ground and PS on to see if you get 12 volts from the power supply. Essentially What's Happening Here is the standby voltage is being sent to the main board but the main board is not doing anything with the voltage as most likely dead ee prom or voltage regulators. In this case you will never get 12 volt or panel on or backlight on. I think with this particular setup you're getting voltage at PS on and I think that needs to be grounded