Guys i got a LC-70LE745U that someone was throwing away so they gave me for free. I had a error code from the tv did research on it found out it was the main. Ordered the main, now i no longer have a error code. GREAT! Now i am not getting any backlight but sharp logo V stays solid (not on the screen). I test the voltages where the led backlight is connected and i am getting 83.2 volts from the 3 positive wires thats connected to the powerboard. I dont know if that is enough to drive those leds. A friend of mine let me borrow his LED tester. I tested each LED wire and im getting the LEDs to power up from there. Im wondering if the PowerBoard is not producing enough voltage to the LEDs. I wonder since the LED tester has voltage regulator everytime i test led wire the voltage drops to roughly 171 each wire. Is that the power that is suppose to be going to each strip? Sorry to sound dumb guys.
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Re: Sharp LC-70LE745U No backlight
Check each string when you first power it on. Record max. voltage of eachI assume no responsibility for any stupid suggestions I might post. -
Re: Sharp LC-70LE745U No backlight
Max 83 on each wireComment
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Re: Sharp LC-70LE745U No backlight
Also on this tv when you remove the back panel you can see the test points for each strip and where the wires get connected. I tested each connection on the strips and it seems to light up each section and the voltage on each strip is 92.2 on the LED tester. Again i dont know if that means anything.Comment
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Re: Sharp LC-70LE745U No backlight
When tv is on what is voltage on main cap? Panel number off panel sticker. Some pictures of power supply.I assume no responsibility for any stupid suggestions I might post.Comment
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Re: Sharp LC-70LE745U No backlight
you can force the set on with some form of "volume up, channel down" (search the forum for the exact sequence) and plugging into power at the same time. This should force on the backlights... go from there. My bet is you have a panel problem.Comment
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Re: Sharp LC-70LE745U No backlight
Yes we tried to force the back light on and nothing. But if i am having a panel issue wouldnt i be getting a error code for hat. Such as 1 slow 1 fast for lamp error. Im not getting any error codes after i replaced the main.Comment
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Re: Sharp LC-70LE745U No backlight
I guess I can throw back the same question, if its an error problem "anywhere" including backlights, shouldn't you be getting a code? :-)
I guess the question would be, are you currently getting any picture / sound? Have you done the "flash light test"?
Of course, the next area of information would be to confirm all the voltages as identified on the various boards (ie. power board, main, tcon)
Lastly, what happens when you do the "disconnect tcon cables" test?Last edited by budwich; 05-03-2017, 02:03 PM.Comment
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Re: Sharp LC-70LE745U No backlight
Yes i did the flash light test and i see nothing. Inhave not tested the voltages yet coming from the main nor did i disconnect the Tcon while the set was on. Let me gove that a try. Thanks guys. I will let you know what i am getting. Sorry to sound nieve but what do you mean the main cap? Thanks again guysComment
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Re: Sharp LC-70LE745U No backlight
So you are missing more than just backlights.
Need voltages from connector that goes from power supply board to main board. Will need pin#- PIN DESCRIPTION -Pin voltage in standby-Pin voltage when pushing power button and picture of connector on power supply board.
Format:
Pin# - Pin Description - Pin Voltage standby - Pin voltage power on
1 - XXXXXXX - XXv - XXXv
2 - XXXXXXX - XXXv - XXXv
3 - XXXXXXX - XXXv - XXXv
4 - etc.I assume no responsibility for any stupid suggestions I might post.Comment
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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 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.
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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... -
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... -
Hello all,
Am trying to figure out this backlight issue with this A1990 Macbook Pro.
Tests performed:
There is no backlight even with a good screen.
Backlight IC is receiving the correct support voltages.
Fuse F8400 ok
Current sense resistor R8400 ok
Backlight IC is receiving 3.3V on enable pin.
Backlight IC receiving voltage from PPBUS_G3H, aprox 12.5V.
Backlight IC receiving 5V from PP5V_G3S
Backlight IC BKLT_SCL and BKLT_SDA both measure 0.545V diode mode to ground
I2C_BKLT_SCL and I2C_BKLT_SDA both measure...
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