Sharp LC-70LE745U No backlight

[Mikeyjohnson]

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.

[dskall]

Re: Sharp LC-70LE745U No backlight

Check each string when you first power it on. Record max. voltage of each

[Mikeyjohnson]

Re: Sharp LC-70LE745U No backlight

Max 83 on each wire

[Mikeyjohnson]

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.

[dskall]

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.

[budwich]

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.

[Mikeyjohnson]

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.

[budwich]

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?

[Mikeyjohnson]

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 guys

[dskall]

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.