Sharp LC-40LE810UN question

[Toppsysoft]

Re: Sharp LC-40LE810UN question

Hello guys, I think I am learning here. I own a sharp tv LC 40LE811E. Just of recent it start to developed fault when it is on after like 15min. The romete and the manual button will seized and stop working until I leave it for a while and power it on again . at time it will on and at times it show standby v light will Bink's 5 times and stop but won't picture out... I have read through the question I can't really find any related to button and remote failure or seize .. Any help I will appreciate...

[stioc]

Re: Sharp LC-40LE810UN question

I just started a new thread but I'm getting the same exact 2 slow 5 fast blinking issue as the OP. Not sure where to go from here. I think someone suggested disconnecting the TCON LVDS cables that go to the panel. they don't seem easy to access but I think I'll try that.

[matyka]

Re: Sharp LC-40LE810UN question

Hi guys, after reading true this I have changed the 4 Cosmo, K1010 B Transistor Output Optocoupler in the TV set LC-40LE811E uses the same power supply and is working now before it had just 2 standby flash.

[dai2bunny]

Re: Sharp LC-40LE810UN question

Hello,

On a Sharp LC-40LE820E with a continuous flashing led and 5V standby only, I solved it like olegi indicated by erasing IC2004. Thank you.

Update:

I had to replace all 4 optocouplers too, because after 10-20 minutes the TV was restarting and entered in a loop. Now it works fine.

[dai2bunny]

Re: Sharp LC-40LE810UN question

Hello,

On a Sharp LC-40LE820E with a continuous flashing led and 5V standby only, I solved it like olegi indicated by erasing IC2004. Thank you.

[Nikolai Tesla]

Re: Sharp LC-40LE810UN question

Dear guys, I have a Sharp LC40LE810 E with a DPS126CP board also. The both axial fuses are blown (3,15A). I cannot find a malfunctioning semi conductor till and up to now, even the Greatz rectifier measures ok with my Fluke multimeter. I understand there are problems with the opto couplers, and as I can imagine, it can damage a SOPS. What shall I do? Replace all 4 opto couplers, but one is different. PC701 is a cosmo 101817, but PC 7702, PC7703 and PC7901 are PC123's. Is this power supply willing to start up with a viariable transformer? (is this is proper English? Such a transformer used in the tube days). Is this power supply runnung stand alone? Any tips to protect this supply from an immediate fuse blow are highly appreciated.

[chip2000]

Re: Sharp LC-40LE810UN question

PC7703 opto chip was found faulty.
Replaced with a PC817 which was an hand, and all is well.

Cheers

THANK YOU!!! For this Help.
I Have an LC-40LX812E with same Blinkcode 2x long 1x short.
Firste i've tried to fix the error with an replacement power supply,
but the replacement wont tv turn on too.
So i changed the optokoppler to the original board and now the tv works!
Many thanks for this infos guys.

Have a nice day!
Greets from germany

[rievax_60]

Re: Sharp LC-40LE810UN question

Good find. The Back Light area looks complicated.

[eduard2]

Re: Sharp LC-40LE810UN question

There the scheme of BP Delta DPS 126 CP without nominations, I have this scheme of the power supply with nominations
PS-can someone and it's useful, I'm new on your site and I'm sorry for my bad English translate it through google translator

[rievax_60]

Re: Sharp LC-40LE810UN question

Yes, it was a difficult fault the find the first time. Just wondering if someone has any thoughts about the deterioration of the optos' CTR?

[SmartSarah]

Re: Sharp LC-40LE810UN question

I had the AC-Det error (2 slow and 1 fast blinks) on a LC-40LE810E. Power at PB connector pins 1-2 and 3-4 came up for a few seconds to 12.9 V and then dropped to zero.
I didn't try anything else except lowering resistor R7019 in series of the opto led from 82K to 30k by adding a 47k in parallel. The TV set runs like a shine now.
Thanks to this board I could skip a whole lot of a hassle digging my way to a solution.
Great work!

[budm]

Re: Sharp LC-40LE810UN question

I found the DPS 126 CP schematic it is used in Grundig KT-Chassis
you can find it by elektrotanya!

Thanks!

[thoma]

Re: Sharp LC-40LE810UN question

I found the DPS 126 CP schematic it is used in Grundig KT-Chassis
you can find it by elektrotanya!

[rievax_60]

Re: Sharp LC-40LE810UN question

Excuse my ignorance, but what does adjusting the pot actually do? Once I dial it in is it something I can leave alone? Why would I need to 'put it back to the same setting later'?

Adjusting the pot might compensate for the reduction of CTR that the original optos seem to suffer from. This loss of CTR is what causes the AC-DET problem and the instability of the back-light power control loop.
It is always a good idea to note the original position of things before they are moved. In this case it might be decided to put the pot back to the original position after the opto is replaced.

[Krebstar]

Re: Sharp LC-40LE810UN question

That is not a good idea. You could adjust the trim pot that is across the LED side of the opto. There are 2 pots. You will have to look at the print to see which is the correct one. Measure the resistance before you move it so you can put it back to the same setting later.

Excuse my ignorance, but what does adjusting the pot actually do? Once I dial it in is it something I can leave alone? Why would I need to 'put it back to the same setting later'?

[rievax_60]

Re: Sharp LC-40LE810UN question

This is the data PDF for the Cosmo opto. Try to work out what the CTR spec is from the info in page 4.

[rievax_60]

Re: Sharp LC-40LE810UN question

That is not a good idea. You could adjust the trim pot that is across the LED side of the opto. There are 2 pots. You will have to look at the print to see which is the correct one. Measure the resistance before you move it so you can put it back to the same setting later.

[Krebstar]

Re: Sharp LC-40LE810UN question

So what are your thoughts about cutting away the back case above those optos to improve air flow? Do you think it would be worth it? I mean the set is working great now. So much so Im debating even putting the case back on .

[rievax_60]

Re: Sharp LC-40LE810UN question

I noticed that the faulty optos were temperature sensitive. Symptoms became worse with increasing temperature. The 817 opto is manufactured by more than one manufacturer.
I pulled mine out of a junked plasma power supply.
There is a bothersome aspect to choosing new parts. There is a wide range in the Current Transfer Ratio spec for the various suffix codes. https://cdn.badcaps-static.com/pdfs/...7b665a5160.pdf
In most circuits the CTR doesn't matter much, so long as it's high enough. I noticed that the opto(PC7701) in the back-light circuit has a trim pot across the LED side. This can only be to adjust for the optos CTR. I would try to get the K817P3.

[budm]

Re: Sharp LC-40LE810UN question

Opto is also sensitive to heat.