Sharp LC-40LE810UN Zero Power

[budm]

Re: Sharp LC-40LE810UN Zero Power

The CTR marking on the opto is H, I believe. It's the bottom letter.

Do you suspect the opto is the issue with those readings on PD?

AC_DET is for protection FOR not allowing the power supply to come on if the AC line Voltage is not within operating range, the PS-ON will not be sent if AC_DET detects problem and sends the error signal to the main board to not send PS-ON signal to turn on the power supply.
So at this point, what is the DC Voltage between pin 3 and pin 4 of that OPTO?

[budm]

Re: Sharp LC-40LE810UN Zero Power

BTW, what DCV do you get on the PD STB (BL-ON) pin?

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

BTW, what DCV do you get on the PD STB (BL-ON) pin?

Do you mean LB STB? That is 0 with power plugged in while pressing power button.

For PC7703 plugged into outlet,
3 - 0.01
4 - 0

PC7901 3&4 is -1
PC7702 3&4 is -1
PC7701 3&4 is -1

[budm]

Re: Sharp LC-40LE810UN Zero Power

Do you mean LB STB? That is 0 with power plugged in while pressing power button.

For PC7703 plugged into outlet,
3 - 0.01
4 - 0

PC7901 3&4 is -1
PC7702 3&4 is -1
PC7701 3&4 is -1

It is LB connector pin SB, I am having a hard time trying to read the prints on the board.
So right now the main board does send out the PS-ON but no PNL_POW and no STB (BL-ON) signal,and you also do not have any indicator lights or any blanking lights error code either. I need to see if I have the service manual for this set.

For PC7703 plugged into outlet,
3 - 0.01
4 - 0

That means the Photo Transistor on the receiving side is turned on, but to be sure, check the DCV on pin 1 & 2 of the Opto just to be sure if the LED on the sending side is on or not.

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

It is LB connector pin SB, I am having a hard time trying to read the prints on the board.
So right now the main board does send out the PS-ON but no PNL_POW and no STB (BL-ON) signal,and you also do not have any indicator lights or any blanking lights error code either. I need to see if I have the service manual for this set.

For PC7703 plugged into outlet,
3 - 0.01
4 - 0

That means the Photo Transistor on the receiving side is turned on, but to be sure, check the DCV on pin 1 & 2 of the Opto just to be sure if the LED on the sending side is on or not.

The service manual is attached on the first post.

Here is a link to a clearer image of the board:
https://i.imgur.com/NT7q0so.jpg

[peterkos2]

Re: Sharp LC-40LE810UN Zero Power

Hi. I had a similar problem on the TV SHARP Aquos LC40LE820. I found out there was a problem with the optocoupler. Even though I pulled it out and measured it looked good. Even so, I changed it and the TV came on. It was an optocoupler PC7703
The TV is still going smoothly.
I originally changed COSMO H to COSMO E

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

Hi. I had a similar problem on the TV SHARP Aquos LC40LE820. I found out there was a problem with the optocoupler. Even though I pulled it out and measured it looked good. Even so, I changed it and the TV came on. It was an optocoupler PC7703
The TV is still going smoothly.
I originally changed COSMO H to COSMO E

Thanks for the info! Does anyone know if 817CN work?

It is LB connector pin SB, I am having a hard time trying to read the prints on the board.
So right now the main board does send out the PS-ON but no PNL_POW and no STB (BL-ON) signal,and you also do not have any indicator lights or any blanking lights error code either. I need to see if I have the service manual for this set.

For PC7703 plugged into outlet,
3 - 0.01
4 - 0

That means the Photo Transistor on the receiving side is turned on, but to be sure, check the DCV on pin 1 & 2 of the Opto just to be sure if the LED on the sending side is on or not.

Pin 1 - -16 then drops to -1
Pin 2 - -1

[R_J]

Re: Sharp LC-40LE810UN Zero Power

Try disconnecting the plug that goes to the panel, labeled PL and see if the UR13.2 stays up.
If you have BU5V you should also have 13.2V on C7962a

[R_J]

Re: Sharp LC-40LE810UN Zero Power

Thanks for the info! Does anyone know if 817CN work?



Pin 1 - -16 then drops to -1
Pin 2 - -1

Pin 1 is connected to VCC1, which is supplied by the standby circuit, if this voltage is dropping, check the connections on the transformer T7901.
The first thing to be sure of is that the standby circuit is working properly, if it is not, the rest of the power supply will not work.

[budm]

Re: Sharp LC-40LE810UN Zero Power

Thanks for the info! Does anyone know if 817CN work?



Pin 1 - -16 then drops to -1
Pin 2 - -1

Pin 1 and 2 are in the hot side, so the circuit ground will be the negative leg of the main filter cap in the hot side. What ground did you use?
And the reason I have you measure right between the two leg so the meter is not reference to the circuit gnd, we are measuring the Vf of the LED inside the Opto.

BTW, when the meter shows -1 that tend to indicate over range.

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

Try disconnecting the plug that goes to the panel, labeled PL and see if the UR13.2 stays up.
If you have BU5V you should also have 13.2V on C7962a

With PL disconnected, UR13.2 drops to zero from 12.5 and 8.5 for each respective pin.

BU5V is up and there is 13.2V on C7962a with PL disconnected.

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

So I went ahead and replaced the Cosmo 817 on PC7703 with PC817CN and the TV now works.

Thank you everyone for their efforts!

[xoicorez]

Re: Sharp LC-40LE810UN Zero Power

I now have another issue. The front panel buttons do not seem to be working, but the standby light works.

[peterkos2]

Re: Sharp LC-40LE810UN Zero Power

Good day. Can you advise me on this problem? TV SHARP Aquos LC40LE820E some time after turning on, something starts blinking as if in the background of the picture. The image is clear, but the flicker is disturbing. When I switch in AV mode to Dynamic Fixed, that's fine. But in other modes it flashes. It looks like a backlight. Thanks for advice.

[peterkos2]

Re: Sharp LC-40LE810UN Zero Power

Good day. Can you advise me on this problem? TV SHARP Aquos LC40LE820E some time after turning on, something starts blinking as if in the background of the picture. The image is clear, but the flicker is disturbing. When I switch in AV mode to Dynamic Fixed, that's fine. But in other modes it flashes. It looks like a backlight. Thanks for advice.

This effect is manifested by about 10-20
minutes after turning on the TV and it takes 25-40 minutes.
I've had it tracked multiple times.

[Cheap TV]

Re: Sharp LC-40LE810UN Zero Power

I also replaced (PC7703) Cosmo 817 with EL817 and the TV (Sharp LC40LE820X) now works perfectly. I had standby 5v, temporary 13V when turned on by remote, no lights at any stage and +Vcc was not switched to PFC controller IC 7801 (NCP1608).