So, I have broken one of my rules and got an LED TV with back-lighting issues. Never had much luck with those, and this one is no different.
TV is LG 42LE5300-UC AUSWLUR with power supply EAY60803201, LED driver board YP4247LPB and main EBU60981905.
When you turn the TV on (with remote or button) PSU relay clicks on, back-lights turn on 2 seconds after that as well as LG welcome screen. After 3 seconds back-lights turn off, but the panel is still on when checking with flashlight test and power supply remains on until turned off by pressing he power button again.
I have taken the panel and filters off to inspect the LED's themselves. It is an edge-lit TV. All LED's turn on with uniformed intensity, none are off or look bad. I have noticed that few LED's have a little glow to them. The glow starts when the set is turned on for those initial 2 seconds, then LED's come fully on, and then they turn completely off after 3 seconds, no glow at the end. I did take a picture of it, but it is hard to see.
I have bypassed the main board as well, just to be sure, be removing the cable that leads to main board from PSU. I have jumped the '3.5V' pin with 'Power ON' and 'DRV On' pins on the PSU. Same problem as before.
Caps look OK and diodes read OK on the PSU. Moving to LED driver board. I do get a 3.3V on the 'ERROR' pin when the back-lights turn off. 'DRV ON' pin remains at 3.3V at all times when PSU is on. There are 13 larger voltage regulators on the LED driver board. When the relay click on, the output voltage spikes to about 36V (I have no min/max) and immediately starts to drop until back-lights come on, then they read 0V. After back-lights turn off, the voltage again spikes to about 36V and settles anywhere from 9.2V to 10.8V on various regulators. The V1+ through V4+ contractually read 98.9V when back-lights are off or 105.5V when they are on.
Any thoughts on what is wrong?
Thanks for the input
Full resolution pictures too larger for BadCaps:
https://www.dropbox.com/sh/dedifsu75...ZyxW9Gcva?dl=0
TV is LG 42LE5300-UC AUSWLUR with power supply EAY60803201, LED driver board YP4247LPB and main EBU60981905.
When you turn the TV on (with remote or button) PSU relay clicks on, back-lights turn on 2 seconds after that as well as LG welcome screen. After 3 seconds back-lights turn off, but the panel is still on when checking with flashlight test and power supply remains on until turned off by pressing he power button again.
I have taken the panel and filters off to inspect the LED's themselves. It is an edge-lit TV. All LED's turn on with uniformed intensity, none are off or look bad. I have noticed that few LED's have a little glow to them. The glow starts when the set is turned on for those initial 2 seconds, then LED's come fully on, and then they turn completely off after 3 seconds, no glow at the end. I did take a picture of it, but it is hard to see.
I have bypassed the main board as well, just to be sure, be removing the cable that leads to main board from PSU. I have jumped the '3.5V' pin with 'Power ON' and 'DRV On' pins on the PSU. Same problem as before.
Caps look OK and diodes read OK on the PSU. Moving to LED driver board. I do get a 3.3V on the 'ERROR' pin when the back-lights turn off. 'DRV ON' pin remains at 3.3V at all times when PSU is on. There are 13 larger voltage regulators on the LED driver board. When the relay click on, the output voltage spikes to about 36V (I have no min/max) and immediately starts to drop until back-lights come on, then they read 0V. After back-lights turn off, the voltage again spikes to about 36V and settles anywhere from 9.2V to 10.8V on various regulators. The V1+ through V4+ contractually read 98.9V when back-lights are off or 105.5V when they are on.
Any thoughts on what is wrong?
Thanks for the input
Full resolution pictures too larger for BadCaps:
https://www.dropbox.com/sh/dedifsu75...ZyxW9Gcva?dl=0
Attached Files
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