Sharp LC-40LE810UN Dead

[alfredomfr1]

No Power, No blinking code.
PD 1-4: fluctuating from 0v to 13v and back again
PD 11: 5v
others PD: 0v
all BL: 0v
all PL: 0v
Main Capacitors: 168v
C7912: fluctuating 14.95 to 16v
R7972: Same as PD 1-4

[budm]

Re: Sharp LC-40LE810UN Dead

So AC_DET is 0V? It should be around 3V if the incoming AC and the detector circuit is OK.
BTW, this should be in the TV section.

[alfredomfr1]

Re: Sharp LC-40LE810UN Dead

and PD-11: 5v, sorry I don't know how to move to the TV section

[budm]

Re: Sharp LC-40LE810UN Dead

and PD-11: 5v, sorry I don't know how to move to the TV section

You report PD-11 which is 5VSTBY, but how about the AC_DET pin of the PD connector? It should not be 0V.
Since you are not even getting the blinking code, I suspect there is problem with the main board.
You need to provide the pictures of the whole back side of the TV showing all the boards.
BTW, the 5Vstby and the 13V are generated by the same transformer so is the 5VSTBY really that steady?
What happen if you run the power supply board by itself then report the Voltages?
Make sure to put down pin name and follow by the Voltage reading for each pin which will make it so much easier without looking at the picture then looking at your pin number.

[yohnsee]

Re: Sharp LC-40LE810UN Dead

Hello,
Referring to your picture:
SG7006 is a spark gap, you don't need to worry about it.
As the secondary 13V fluctuates, is the voltage on the main filter caps steady? Does it do the same when you disconnect the main?
Edit: maybe the PFC tries to start, but can not for whatever reason.

[yohnsee]

Re: Sharp LC-40LE810UN Dead

Maybe this helps, today I do not have any brainpower left to check it, but you can look it trough, if it is more or less the same as your board.
(I would say yes)

[alfredomfr1]

Re: Sharp LC-40LE810UN Dead

This is an update

PD-1-2 UR13.2V (signal): Fluctuating 0 to 13v and again 0 to 13v
PD-3-4 UR13.2V (Audio): Fluctuating 0 to 13v and again 0 to 13v
PD-5-6 SGND (signal)
PD-7-8 SGND (audio)
PD-9 AC-DET: 0v
PD-10 PS-ON: Fluctuating 0 to 3v and again 0 to 3v
PD-11 BU5V: 4.99v to 5v not variation
PD-12 PNL-POW: Fluctuating 0.06v to 0.75v and again 0.06 to 0.75v

[alfredomfr1]

Re: Sharp LC-40LE810UN Dead

Pictures Update

[alfredomfr1]

Re: Sharp LC-40LE810UN Dead

yohnsee, main filter voltage steady with Main Board connected or disconnected.
No 13v with Main Board disconnected

[Davi.p]

Re: Sharp LC-40LE810UN Dead

This board have often the same two problems, first of all feed the psu separately and switch it all on with a pull up on the ps-on pin, now check voltages, if you have no ac-det signal high but the 5v and the 13v then change the optocoupler 7730 then retry, if this time you have ac-det then redo the same test but this time after checking the 13v pull high the pnl_pow then check the 4 pin connector that feeds the tcon, if you have no 12v then change the 4 pins KIA regulator under heatsink.

[budm]

Re: Sharp LC-40LE810UN Dead

OK, so you do have fluctuating PS-ON, not 0 Volt as you reported in post #1, that is why the switched 13V is fluctuating.

[alfredomfr1]

Re: Sharp LC-40LE810UN Dead

budm: Yes, my mistake
Davi.p: How can I test the psu separately?

[Davi.p]

Re: Sharp LC-40LE810UN Dead

What do you think i have said in post #10?

[sda]

Re: Sharp LC-40LE810UN Dead

This board have often the same two problems, first of all feed the psu separately and switch it all on with a pull up on the ps-on pin, now check voltages, if you have no ac-det signal high but the 5v and the 13v then change the optocoupler 7730 then retry, if this time you have ac-det then redo the same test but this time after checking the 13v pull high the pnl_pow then check the 4 pin connector that feeds the tcon, if you have no 12v then change the 4 pins KIA regulator under heatsink.

Thank you.
Only 5V stby on main - no AC-det voltage
Faulty o/p (7703)

Cheers