Sharp LC-46LE820X Lamp error

[rahulmadhukar]

Hi friends, I have a Sharp 46" LED TV model - LC-46LE820X. I got it from a friend who told me that it is not starting up at all. When investigated noticed that the central icon blinking twice which suggest a lamp error code as per the service manual. I tried to reset it by holding Volume -, Channel up and power. This resulted in stabilising the central icon and I was able to switch on the tv.

I plugged in the antenna and I could hear the sound but the backlit is not on. When tried to switch on the TV in dark I could see that the backlit tried coming on for less than a second only. I have never troubleshooted a backlit problem before. I don't even know whether I should be getting AC or DC voltage at the terminals which connects the backlit. So need your help to guide me what to do next. I also took the reading of the terminals as per the photos, all looked to be normal but didn't find any voltage on the terminal connecting the LED's, neither AC nor DC. Also I found 3.26V DC on ERROR pin of one connector(please refer pics to know which connector).Not sure which one to consider or which one to ignore....

I also tried removing both the LED connectors one by one but that didn't made any difference. I have a multimeter and the zeal to learn, so please guide me through this guys. Thanks.

[Kilroys]

Re: Sharp LC-46LE820X Lamp error

2 times blinking indicate power failure
What happens if you press the menu button on the remote ?
Blink first 2 times and then .....?

[freakaftr8]

Re: Sharp LC-46LE820X Lamp error

Try this. Unplug tv. Now plug in. Is it flashing one long one short blink again? If so. Hold input and vol- and press power. Does the light come on steady? Any backlight action?

[rahulmadhukar]

Re: Sharp LC-46LE820X Lamp error

Hi Kilroys and freakaftr8 for your suggestions, here are the findings....

When I press the menu the the blinking pattern changes to one slow blink and one fast blink and it keeps repeating.

When I hold volume -, Source and power together then the blinking stabilizes. Now I was able to turn on/off the tv normally. The only problem is the backlight not turning on. I see that the LED backlit try to switch on for a microsecond but they go off after that. I can hear the sound and also the LCD screen showing some faint shadows of the picture. The only thing missing is the backlit LED. When I check voltages to the red/blue cables going in the screen for LED backlit then there is no voltage, only some in mV.

Can anyone tell me how to verify if the fault is in the power board or in the LED itself... Thanks in advance.

[freakaftr8]

Re: Sharp LC-46LE820X Lamp error

Well to me it sounds as if its a backlight error. The fact that the backlights attempt to come up means a short somewhere in one of the led strips.
Oddly though normally sharps like to go out.altogether. if a backlight error is recognized then a full shutdown happens. Somehow the backlight error is being bypass and this set attempts to power up and stays on. At this point you could try disconnecting one of the backlight connectors and attempt to power the setup using the method I described see if half of the screen is lit if not reconnect that connector and disconnect the other and then power up using my method and see if half the screen lights then

[rahulmadhukar]

Re: Sharp LC-46LE820X Lamp error

Hi freakaftr8, I tried connecting both the wires one by one but same results. None of the backlight LED turned on. Just wondering whether I will be getting any kind AC/DC voltages on them as the TV is running? Also if the LED strips are short then how can I check for it... are they repairable or they needs to be changed thoroughly? Thanks.

[freakaftr8]

Re: Sharp LC-46LE820X Lamp error

Roughly 380 to 400vdc feeds the LED strips. But your getting a shutdown.. Here read up on this to get a broader idea, of course this is the LC-60LE810UN model but yours is typically the same design, just smaller screen.

https://www.badcaps.net/forum/showth...le810un&page=3

[budm]

Re: Sharp LC-46LE820X Lamp error

If you know how to use your meter in DC A mode, you can try measuring the current draw in each string (you will have to break the wire and put the AMP meter in series with the LED string), the one with open LEDA will show 0A, or if the wire is shorted to the chassis, you can check the resistance of the LED feeding wires and the chassis (you have to unplug the connector that feeds the LED.
Typical LED drive power supply will detect open circuits and shorted circuit.

[Kilroys]

Re: Sharp LC-46LE820X Lamp error

I have had a 40le820 a couple of years ago
with no voltage on led_drv. Dont remember the blinking code.
A closer look showed a short D7605 diod at pin 19 IC7601.
The customer had warranty so I ordered a new power supply.

[rahulmadhukar]

Re: Sharp LC-46LE820X Lamp error

I have had a 40le820 a couple of years ago
with no voltage on led_drv. Dont remember the blinking code.
A closer look showed a short D7605 diod at pin 19 IC7601.
The customer had warranty so I ordered a new power supply.

Hi mate, thanks for sharing the cct diagram and suggestion. I checked that diode but it is good.

I spent half the day checking the LED strips. What I did was, I took out all the four LED strips (2 top + 2 bottom) from the screen. In order to check the LED's I switched off/on the tv again and again using remote. Whenever I switched on the TV the LED's came on for a fraction of a second. So I concentrated on each strip one by one to find any LED which does not glow. But all the LED's were glowing. Not sure my method to find a faulty LED is good or bad, but that was the easiest way.

One thing to be noticed was that sometimes the LED strips were not as bright as should be even though they glowed for sure. And after few more tries the LED's were bright again. Does this mean that the LED's are not getting enough power from the power board? Not sure why is this happening. Should I replace the power supply straight away or is there any other test I can do to isolate the problem. Thannks in advance.

[Kilroys]

Re: Sharp LC-46LE820X Lamp error

If you had a broken led and hold volume -, Source and power together then
you override the protection and should have a screen with a dark line where
the led doesnt light.

[rahulmadhukar]

Re: Sharp LC-46LE820X Lamp error

If you had a broken led and hold volume -, Source and power together then
you override the protection and should have a screen with a dark line where
the led doesnt light.

It is an edge-lit LED tv. Should it show me the dark area just like in the pics? Thanks.

[freakaftr8]

Re: Sharp LC-46LE820X Lamp error

Good job so far! Before you assemble try to test the diodes individually with a meter in diode check mode and watch them light up with your meter. Read the meter at the same time. Its tedious but if all is well your in the same boat as me with a sharp lc-80le632u. All light up but still get the error. I used this method to get past the error.

Hold vol- and ch- and plug in at the same time you are holding these two buttons. That may not be the method for yours. I believe your method is unplug. Plug in. Hold vol- input and press power. When the inverted v goes solid release all buttons.

[freakaftr8]

Re: Sharp LC-46LE820X Lamp error

I also might when I came across the defective led it was the first one that connects to the power connector on the strip and although it still lit up my meter it was showing nothing way off measurement although it did light up just barely so you coulD still have that led bad
what you should do is a little more in depth with a meter Instead of powering it up

[f.earl]

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