This one wasn’t an interesting repair from economic point of view, but since I already had fixed first symptom, I decided to go on with the other.
The first symptom (white screen) would be clear if it was an AUO panel, but it’s a Chimei V315B1-L07. Since it’s a MVA panel, it’s "dead" state is black, so the T-CON is alive. I cannot control the TV and I cannot inject any image to check if there’s something beyond the white fog. I check T-CON and it carries a AS15-G. Replace it with AS15-F and done.
Now the TV has another issue. After powering on it ignores the remote control for seconds, then the LED blinks when receiving IR signal, but nothing happens on screen. After some time, it can show the Menu, but if you try an automatic tuning, it keeps frozen at 0%, with no progress.
I search the web for common issues in this model and I found something related to voltage regulator IC903 Semtech SC1565I5M-1.8 (BTW, it’s incorrectly spelled as SC156515M-1.8 in the Service Manual and in many other websites). IC903 outputs 1.8V correctly, but then I see another one, IC501, that outputs nothing, it’s enabled and it has 3.3V input.
Funny thing: Service Manual lists part IC501 but it isn’t shown in schematics!! Since it’s adjustable, I don’t know which voltage is expected from it. I check adjust resistors R521 and R522 (910Ω and 9400Ω) and, according to the formula (see regulator datasheet), it has to output 1,31V. Then I check the 1V2, 1.2V and 1.2VA lines from schematic. I detect a low resistance (not a short) after L102. I remove it and now the voltage regulator has a normal resistance value, but it keeps delivering 0.5V. Replace it and now it outputs 1.3V OK. Check C118 ESR and it’s 20Ω. Replace it and put L102 back in place again, fixed!
The first symptom (white screen) would be clear if it was an AUO panel, but it’s a Chimei V315B1-L07. Since it’s a MVA panel, it’s "dead" state is black, so the T-CON is alive. I cannot control the TV and I cannot inject any image to check if there’s something beyond the white fog. I check T-CON and it carries a AS15-G. Replace it with AS15-F and done.
Now the TV has another issue. After powering on it ignores the remote control for seconds, then the LED blinks when receiving IR signal, but nothing happens on screen. After some time, it can show the Menu, but if you try an automatic tuning, it keeps frozen at 0%, with no progress.
I search the web for common issues in this model and I found something related to voltage regulator IC903 Semtech SC1565I5M-1.8 (BTW, it’s incorrectly spelled as SC156515M-1.8 in the Service Manual and in many other websites). IC903 outputs 1.8V correctly, but then I see another one, IC501, that outputs nothing, it’s enabled and it has 3.3V input.
Funny thing: Service Manual lists part IC501 but it isn’t shown in schematics!! Since it’s adjustable, I don’t know which voltage is expected from it. I check adjust resistors R521 and R522 (910Ω and 9400Ω) and, according to the formula (see regulator datasheet), it has to output 1,31V. Then I check the 1V2, 1.2V and 1.2VA lines from schematic. I detect a low resistance (not a short) after L102. I remove it and now the voltage regulator has a normal resistance value, but it keeps delivering 0.5V. Replace it and now it outputs 1.3V OK. Check C118 ESR and it’s 20Ω. Replace it and put L102 back in place again, fixed!
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