Hello, so I have a backlight issue that's driving me insaine.
The tv is an AKAI 55” 4K ect ect, tv that turned on but no backlight.
Used a backlight tester and of course, no lights. So spent the good part of 2 millenniums taking off the panel, replacing a single blown LED, testing with my LED tester again, they all turned on, however slightly dim. Put the tv back together and .... nothing....
To make a long story short, the power supply ramped up to the 140-170v to run the backlights but after a second the voltage drops down to 0v, and the tv keeps starting as normal. (And no visible lighting up at all) it does the same weather the backlights are plugged in or not, all standby, power_on, adjustment , backlight ect voltages are all there and normal.
I even went as far as to get another similar power supply to test with, now it's ramps up to 150-180v and stays there (adjustment work too) however no visible backlight. Now In a dark room you can see in the holes in the back the lights are actually on but very dim. And I'm not sure why.....
Now initially I tested each strip Separately and all as a complete circuit and all worked (again, however it seem a little dim) after I replaced the one LED and all the lights were about the same, so why on earth is the backlight not getting to full brightness?
Could the new LED be causing the whole circuit to be dim? Or could there of been some kind of surge that damaged a lot more LED's? At this point I'm going to assume that the backlight driver is fine and something is going on with the lights themselves, there was some slight burn (heat) marks where the backlight wire was but I test the voltage and resistance of the wire and it seems perfect.
So before I have to pull the bloody LCD off again does anyone have any idea what's going on? Or have I missed somthing?
On a side question, how forgiving are LED strips and/or driver circuits if I was to pull a set of backlight strips off another tv To test? I mean if it was a few LEDs less or More Would it still work? And could I use a filament 240v globe to test the driver output of would the draw stress the driver too much?
Any help or ideas highly appreciated, still using a 32” Samsung plasma from colonial times as I'm poor, 4K would be very nice
Cheers,
The Todd
The tv is an AKAI 55” 4K ect ect, tv that turned on but no backlight.
Used a backlight tester and of course, no lights. So spent the good part of 2 millenniums taking off the panel, replacing a single blown LED, testing with my LED tester again, they all turned on, however slightly dim. Put the tv back together and .... nothing....
To make a long story short, the power supply ramped up to the 140-170v to run the backlights but after a second the voltage drops down to 0v, and the tv keeps starting as normal. (And no visible lighting up at all) it does the same weather the backlights are plugged in or not, all standby, power_on, adjustment , backlight ect voltages are all there and normal.
I even went as far as to get another similar power supply to test with, now it's ramps up to 150-180v and stays there (adjustment work too) however no visible backlight. Now In a dark room you can see in the holes in the back the lights are actually on but very dim. And I'm not sure why.....
Now initially I tested each strip Separately and all as a complete circuit and all worked (again, however it seem a little dim) after I replaced the one LED and all the lights were about the same, so why on earth is the backlight not getting to full brightness?
Could the new LED be causing the whole circuit to be dim? Or could there of been some kind of surge that damaged a lot more LED's? At this point I'm going to assume that the backlight driver is fine and something is going on with the lights themselves, there was some slight burn (heat) marks where the backlight wire was but I test the voltage and resistance of the wire and it seems perfect.
So before I have to pull the bloody LCD off again does anyone have any idea what's going on? Or have I missed somthing?
On a side question, how forgiving are LED strips and/or driver circuits if I was to pull a set of backlight strips off another tv To test? I mean if it was a few LEDs less or More Would it still work? And could I use a filament 240v globe to test the driver output of would the draw stress the driver too much?
Any help or ideas highly appreciated, still using a 32” Samsung plasma from colonial times as I'm poor, 4K would be very nice
Cheers,
The Todd
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