Re: Sharp LC-40LE550U no backlight
ok cool, i'll go ahead and set it to a comfortable low level before it goes to a new home.
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Re: Sharp LC-40LE550U no backlight
They should have good thermal management, I would set the BACKLIGHTS LEVEL (not the brightness/contrast) to as low as you can so the LEDs will run cooler and extend the life of the LEDs.Leave a comment:
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Re: Sharp LC-40LE550U no backlight
crazy thing is that four out of 5 led strips are mounted to the panel casing which is plastic, only the second strip from the top is mounted on a strip of metal. I was under the assumption that the LED strips needed to be mounted to metal which acts as a heatsink?Leave a comment:
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Re: Sharp LC-40LE550U no backlight
I believe it was 10 LEDs per strip 5 stripsLeave a comment:
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Re: Sharp LC-40LE550U no backlight
So how many LEDs are in one strip? 4 LED strips?Leave a comment:
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Re: Sharp LC-40LE550U no backlight
disassembled the panel to test the leds, found bad solder joints on one the of the connectors that join the two separate strips into one long strip. turned it on and the leds blinded me.Last edited by krygods; 10-09-2015, 03:55 AM.Leave a comment:
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Re: Sharp LC-40LE550U no backlight
BTW, what is the marking in IC UD101, just right of 47uF 450V cap?Leave a comment:
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Re: Sharp LC-40LE550U no backlight
Hmm, from
https://www.sharpusa.com/ForHome/Hom...C40LE550U.aspx
4 million: 1 dynamic contrast ratio
Without even seeing the TV, I think I will call
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Re: Sharp LC-40LE550U no backlight
It would make things easier for us if you put the description of each pin next to the readings.
CN201
pin 3 - ACD
pin 14 - BL_ON
On most sets, BL_ON (backlight on) going high (> 3) means turn on. On some sets, it might be the opposite.
ACD might be AC Detect. On some sets, ACD high might be needed to turn on. Or it could be the opposite.
When the TV is in standby mode, what is the voltage of pins 3 and 14? When turned on what is the voltage of 3 and 14? When the set is turned off, what is the voltage of 3 and 14?
Wow, 329V DC into the LEDs. Nearly a 55 to 52 volt drop between each strip of LEDs. At least it has decent 47uF 450V cap there.Leave a comment:
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Sharp LC-40LE550U no backlight
This TV powers on and off and I can see the floating screen saver very faintly with a flashlight.
I've measure voltages and here is what I've found
CN201
1 - 3.25VDC
2 - NC
3 - 112mVDC
4 - 3.19VDC
5 - GND
6 - GND
7 - GND
8 - GND
9 - 12.45VDC
10 - 12.45VDC
11 - 12.45VDC
12 - 12.45VDC
13 - 375mVDC and rising???
14 - 3.18VDC
15 - 0.67VDC
16 - NC
CN202
1 - 329VDC
2 - GND
3 - 275VDC
4 - GND
5 - 221VDC
CN203
1 - GND
2 - 168VDC
3 - GND
4 - 116VDC
5 - GNDAttached FilesLast edited by krygods; 10-08-2015, 11:13 PM. -
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Hello Sharp TV experts
Our Sharp LC-80LE642U displays one short one long flash error code which is a backlight error. I went into service mode and there were 8 lamp error counts recorded. I reset the count to 0 and did a reset. The last monitor error cause was 16 B00014639:12. 16 is the code for backlight error. I tried to power the tv up but went back into error mode.
> I checked voltages on the power supply board and they all check out .. including 3.28 volts at the error pin.
> There is power to the cpu and T-CONN and no faults found there. The cpu has a flashing...01-24-2025, 11:51 PM -
This set has the known reputation of failed led backlights. The set does not turn on, but when plugged in, the power led stays lit for about 5 seconds followed by two short blinks and then it repeats itself. While shinning a flashlight on the screen, you can make out the Sharp logo, then it goes out and repeats the cycle. I measured some voltages across the led backlight connector. What has me puzzled is that when I place the negative lead of my vom on the led backlight pin connector (in which the black wire going to the leds was), I measure as high as -228volts, and then it falls to -95 volts... -
this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even... -
I have a sharp LC-50LB601U that has no backlight. It starts up fine, and has sound, however, I can only see the screen using a flashlight. I took the tv back off and measured voltages at the power supply connector CN-8601. As you can see by the picture, the led connector has 2 sets of 2 red wires and 2 sets of black wires going to the led backlights. Between each set of black wires and corresponding red wires, I measure 30 volts (pins 1 and 4) and 30 volts from pins 8 and 12. From ground to each set of red wires ( pins 1 and 12 to ground), I measure 35 volts. This voltage seems very low compared...
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I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered...
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