I have recently come into a bunch of TV's for cheap and they all need repair. I've had success with getting one working, in an odd ball way so I am here for advice or recommendations.
First the conditions of the TV's:
I have 3 LG 47LN5400, one LG 55LB5900 (broken panel) that I am working with (I have a few others 50" and 42" but they have broken panels that I am not going to bother with besides for parts.
The 3 47" LG's I am trying to fix all have the same problem. When powering on, the backlight comes on for a split second and turns back off. When the backlight is off, I've done the flashlight test and the image is still there. This tells me the main board is likely fine. All the caps look in mint condition and there isn't any obvious damage such as arcing or black burn marks. I've been reading some threads and have done some measurements and I will post those later.
In order to test the 3 47" LG's I took the powersupply from the 55" LG with the broken screen and tried each one, and the TV's work flawlessly so that limits the problem to the power supplies of the 47" TV's.
In my searching I cam across this image, where someone kindly layed out the parts of my PSU
https://www.badcaps.net/forum/attach...1&d=1430269466
I did some measurements like the thread suggested at Filter Caps 1, and Filter CAPs 2, and here are the results.
Filter Caps 1: 78v (peaks at 103v when backlight turns on then off)
Filter Caps 2: 75v (peaks at 182v when backlight turns on then off)
In another thread a similar issue arrised and they said the problem is the LED drive controller IC, which makes sense since when I swapped the other larger power supply in from the 55" TV, everything worked fine.
Here is some other info:
47" TV model number: 47LN5400
47" power supply model/serial number: EAX64905501 (2.0) Rev 1.0
55" TV model number: 55LB5900
55" power supply model/serial number: EAX 65423901 (2.1) Rev 2.0
-------------------------------------------------------------
So I guess the real question is, is it possible to purchase these IC's to solder them on, or is there a cheap place to buy new power supplies?
Also is it safe to use the 55" LG TV power supply in the 47" TV? The PCB physically doesn't fit so I will have to make my own mounts and cut a hole in the back plastic casing, but other than that is there any risks?
Like wise I have a 42" TV with a smashed panel but the backlights stay on so I assume the PSU is good, but it only supports power to 1 LED string. Can I remove the LED controller from this and use it on a 47" LG PSU?
Thanks!
Edit: I am not 100% positive that it is the LED controller, but from what I read, it sounds like it could possibly be it. Any testing/tips will be appreciated.
First the conditions of the TV's:
I have 3 LG 47LN5400, one LG 55LB5900 (broken panel) that I am working with (I have a few others 50" and 42" but they have broken panels that I am not going to bother with besides for parts.
The 3 47" LG's I am trying to fix all have the same problem. When powering on, the backlight comes on for a split second and turns back off. When the backlight is off, I've done the flashlight test and the image is still there. This tells me the main board is likely fine. All the caps look in mint condition and there isn't any obvious damage such as arcing or black burn marks. I've been reading some threads and have done some measurements and I will post those later.
In order to test the 3 47" LG's I took the powersupply from the 55" LG with the broken screen and tried each one, and the TV's work flawlessly so that limits the problem to the power supplies of the 47" TV's.
In my searching I cam across this image, where someone kindly layed out the parts of my PSU
https://www.badcaps.net/forum/attach...1&d=1430269466
I did some measurements like the thread suggested at Filter Caps 1, and Filter CAPs 2, and here are the results.
Filter Caps 1: 78v (peaks at 103v when backlight turns on then off)
Filter Caps 2: 75v (peaks at 182v when backlight turns on then off)
In another thread a similar issue arrised and they said the problem is the LED drive controller IC, which makes sense since when I swapped the other larger power supply in from the 55" TV, everything worked fine.
Here is some other info:
47" TV model number: 47LN5400
47" power supply model/serial number: EAX64905501 (2.0) Rev 1.0
55" TV model number: 55LB5900
55" power supply model/serial number: EAX 65423901 (2.1) Rev 2.0
-------------------------------------------------------------
So I guess the real question is, is it possible to purchase these IC's to solder them on, or is there a cheap place to buy new power supplies?
Also is it safe to use the 55" LG TV power supply in the 47" TV? The PCB physically doesn't fit so I will have to make my own mounts and cut a hole in the back plastic casing, but other than that is there any risks?
Like wise I have a 42" TV with a smashed panel but the backlights stay on so I assume the PSU is good, but it only supports power to 1 LED string. Can I remove the LED controller from this and use it on a 47" LG PSU?
Thanks!
Edit: I am not 100% positive that it is the LED controller, but from what I read, it sounds like it could possibly be it. Any testing/tips will be appreciated.
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