Short answer: main board.
Long answer:
Someone gave me a Vizio D50u-D1 that had a standby light but would fade out when the power button was pressed. No video, no backlight, may as well as be unplugged. Research indicated a bad main board which I could replace with a used one for $50 or a rebuilt one for $65. Either way, what's the point? If it's designed to bake itself to death in 5 years (TV is a 2015 model), why bother?
For the hell of it, I tested the LEDs. They were fine. Power button? Working just fine. Once again, why bother doing anything else? Just trash the thing already. Not worth putting money into.
Well...it is the day before Thanksgiving and I'm bored, so...let's see what we can do. This is actually my favorite part of troubleshooting, the part I call "autopsy mode", where I don't care what I break, I'm going to figure out what the original issue was.
I took the main board off, removed its heat shield, and applied about 400 degrees of hot air to the two processors on it (about 3 minutes per processor) and left it to cool for a half an hour. I wiped off as much of the white thermal paste I could and applied some CPU thermal grease to the cores (I used arctic silver), reassembled everything, and the TV actually turned on. I couldn't believe it.
But now what? It's not a permanent solution and it's just going to die again anyways due to the crappy design.
No pics right now but I decided to take a 12V CPU fan, glued it to the middle of the main board's heat shield (blowing into it), used an old 12V 2 amp power supply to power it, cut a square hole into the back side of the TV cover, and it's all benching now. Who knows if it'll last.
Fun fact: this is the first time "reflowing" has worked for me, thus my surprise. Happy Thanksgiving, y'all.
Long answer:
Someone gave me a Vizio D50u-D1 that had a standby light but would fade out when the power button was pressed. No video, no backlight, may as well as be unplugged. Research indicated a bad main board which I could replace with a used one for $50 or a rebuilt one for $65. Either way, what's the point? If it's designed to bake itself to death in 5 years (TV is a 2015 model), why bother?
For the hell of it, I tested the LEDs. They were fine. Power button? Working just fine. Once again, why bother doing anything else? Just trash the thing already. Not worth putting money into.
Well...it is the day before Thanksgiving and I'm bored, so...let's see what we can do. This is actually my favorite part of troubleshooting, the part I call "autopsy mode", where I don't care what I break, I'm going to figure out what the original issue was.
I took the main board off, removed its heat shield, and applied about 400 degrees of hot air to the two processors on it (about 3 minutes per processor) and left it to cool for a half an hour. I wiped off as much of the white thermal paste I could and applied some CPU thermal grease to the cores (I used arctic silver), reassembled everything, and the TV actually turned on. I couldn't believe it.
But now what? It's not a permanent solution and it's just going to die again anyways due to the crappy design.
No pics right now but I decided to take a 12V CPU fan, glued it to the middle of the main board's heat shield (blowing into it), used an old 12V 2 amp power supply to power it, cut a square hole into the back side of the TV cover, and it's all benching now. Who knows if it'll last.
Fun fact: this is the first time "reflowing" has worked for me, thus my surprise. Happy Thanksgiving, y'all.
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