Sharp aquos LC-40LE810E

[Nightmare0]

Re: Sharp aquos LC-40LE810E

(PD-1-2)UR13.2V(SIGNAL): 13.01V
(PD-3-4)S13V.2(AUDIO): 13.01V
(PD-5-6)SGND(AUDIO): 0V
(PD-7-8)SGND(SIGNAL): 0V
(PD-9)AC-DET: 0V
(PD-10)PS-ON: 3V
(PD-11)BU5V: 4.99V
(PD-12)PNL-POW: 0V

I am getting these voltages only when I plug tv to power. Because after while, tv will show error code and only 5v is present. Should I try that resistor on top of that second resistor?

[rievax_60]

Re: Sharp aquos LC-40LE810E

(PD-1-2)UR13.2V(SIGNAL): 12.9V
(PD-3-4)S13V.2(AUDIO): 12.9V (its not misspelled, its written like this)
(PD-5-6)SGND(AUDIO): 0V
(PD-7-8)SGND(SIGNAL): 0V
(PD-9)AC-DET: 0V
(PD-10)PS-ON: 3V
(PD-11)BU5V: 4.9V
(PD-12)PNL-POW: 0V

What are these voltages now? Keep in mind that some of these voltages might not stay up for long after the mains is applied.
I think AC-DET can only be high when PS-ON is high. It has been a few months since I worked on s similar model here.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

Here are photos after I put all original optos back. You can check, they are in same position. I added photo from shopjimmy so you can check they are really in proper way. Also photo of that red led. Red led is not still on. It is flashing like: maybe 20 seconds on, off for few seconds afaing 20 seconds..... after few flashes, led will turn off and nothing else happens.
I was not using TV with this fix. I tried that once, when I first tried for maybe 30 seconds until I took photo.
After opto change, it started to act like that. So how bad is it? All pins have same voltage. If you need more info just let me know.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

Here are photos, after I changed all optos. I noticed they are not same brand. 2 of them were sharp and 2 of them different. Also I checked if I am fitting them in correct way. There is sign 1 on motherboard for dot in left top corner. Also there are marks on side and motherboard like half circle. So I am sure I fitted them correctly.

[fzabkar]

Re: Sharp aquos LC-40LE810E

"I took out pin 9 - AC-DET an just plugged it next to pin 11 - 5v. Without any soldering. It's just touching and TV has started up. Everything seems to be working."

The AC-DET signal is normally tied to the supply via a pullup resistor. By connecting pin 9 directly to the BU5V supply pin, you would have impressed the supply voltage directly onto an MCU GPIO pin. This is not always a safe thing to do.

Edit: IC2002 is powered from BU+3.3V, so impressing BU5V onto its AC_DET pin would have resulted in latchup without any current limiting. I could be wrong, though.

[rievax_60]

Re: Sharp aquos LC-40LE810E

The first thing to check is that the optos are fitted the correct way. They dont all face the same way. Take a clear photo of the top before you do anything else.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

I was celebrating too soon.

I changed all optos. Measured all pins...getting same voltage on all pins like before. Tried that magic trick with resistor again, but this time tv didn't turned on. Not even led. Just red led on mainboard.
I put all original optos back. Same... Red led on mainboard. When start without that resistor trick, tv is still flashing with same error.code. getting same voltages. Just resistor trick doesn't work anymore.
Could I burn optos? Or I really screwed something? I will send you photos tomorrow, I am sad and tired, so I am going to sleep now. But there weren't any cold joints, bridges, used flux, everything seemed nice.

[rievax_60]

Re: Sharp aquos LC-40LE810E

The function of the AC-DET is also to warn the controller of imminent loss of supply rails so that it wont risk writing to memory resulting in corruption.

[budm]

Re: Sharp aquos LC-40LE810E

Glad to hear, so now we know that it is the AC-DET failure only, so it is either the resistor for the circuit is marginal or changed in value (goes higher resistance), or bad opto per suggestion by other members.
The purpose of the AC-DET is not to allow the TV to come on if the AC Voltage feeding the TV is too low, so right now it is the protection circuit is causing the fault due to its own failure.

[rievax_60]

Re: Sharp aquos LC-40LE810E

If you do not restore proper function of the AC-DET, you will risk EEPROM corruption. Your TV will have similar function to that of a brick.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

Wow. You guys are awesome ! Real professionals.
I took out pin 9 - AC-DET an just plugged it next to pin 11 - 5v. Without any soldering. It's just touching and TV has started up. Everything seems to be working.
I will test it tomorrow. If you want, I can make some measurements for you. Is there anything that I should check before soldering it? I will also keep that 68k resistor and optos for future.

/edit
I added quick photos I will post more, when You allow me to solder that.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

Ok. I have bought resistors. 560 ohm for AC-DET fix.
Also bought 68k smd resistor and also 33k and 4 opto-couplers.
First I will fix that AC-DET and will post results.

Also I got crazy idea. If everything fails, is it possible to buy some lvds to hdmi converter and use this tv only for set-top box? I don't want to do that now. Just if it is possible

[budm]

Re: Sharp aquos LC-40LE810E

I do not know what the main board will do when it detects AD-DET problem, I would it should take away the PS-ON signal and then blink and error code, but in this one the PS-ON is still present, it may be true that it will shut down the panel Voltage, that is why he need to fool the main board that AC-DET is OK by pulling the line high and see what will happen next which is what I am waiting to see the result when he gets the resistor.
I believe PNL-PWR is the command pin form the main board, there should be another connector on the power supply board with '12V_PNL' that goes to the T-CON board.

[fzabkar]

Re: Sharp aquos LC-40LE810E

So so far you do have power supply board problem due to AC-DET circuitt, and then then PNL-PWR problem.

Couldn't the main board be switching off PNL-PWR in response to the AC-DET failure?

[rievax_60]

Re: Sharp aquos LC-40LE810E

That's right, the 68k is soldered on top of the the existing 82k or replace it totally with a 33k. Its best to search for the PC817 opto to find what's best available in your area.
Or just play it safe and do nothing else if the resistor mod works.

[Nightmare0]

Re: Sharp aquos LC-40LE810E

not yet. I will read whole thread soon.
you mean that 68k resistor fix? I can try that. Also can you help me to find replacement for optocouplers? In that thread someone use PC817. Can I try them too?

[rievax_60]

Re: Sharp aquos LC-40LE810E

What are optos, are they easy to get and replace? How much they cost? won't be easier to buy whole power supply?

The full name of the part is "opto-coupler". Did you look at the other thread? it explains more including a temporary fix. All if your TV has the same problem.
https://www.badcaps.net/forum/showth...AC-DET&page=14

[Nightmare0]

Re: Sharp aquos LC-40LE810E

What are optos, are they easy to get and replace? How much they cost? won't be easier to buy whole power supply?

[rievax_60]

Re: Sharp aquos LC-40LE810E

If it is the AC-DET problem, I recommend that all 4 optos be replaced. Read the other thread.

[budm]

Re: Sharp aquos LC-40LE810E

Anything between 330~1K will be fine.
"And what about that PNL-POWER?" That is another problem.
So so far you do have power supply board problem due to AC-DET circuitt, and then then PNL-PWR problem.