I've searched what I could, but did not find the relationship between blown Mosfets and other problems on (or off) the Vizio inverter boards. My Master inverter board (6632L-0470A) looks like it has a partially "blasted" pin on the main integrated circuit (pin 26, I think). And when I measure across the Mosfets, one of them (MQ1) measures 76 ohms, so I expect it, or something else in it's circuit, is blown. Other Mosfets on the Master and Slave inverter (6632L-0471A) cards measure 8.5K as expected (according to other posts). None of the caps looks puffed. And the fuses on both boards measure OK (0 ohms).
As for TV symptoms...there is no backlight, but there is an image on the screen when shining a flashlight on it with Menu selected. The backlight does not flash when the TV is turned on. I can't tell if there is working sound since I can't easily select an input, but I expect there is no sound.
All this seems to point to classic inverter board failure, and I am considering options to fix it. Just changing the caps seems like it won't do the job if a Mosfet and an IC are blown. Is that the general wisdom here? Putting in a "kit" to replace the mosfets and the IC is a real hassle (especially for the IC). And it may not fix the root cause that blew them in the first place, which may have been a bad Capacitor. And are there reasons other than a bad capacitor that might blow a mosfet and the IC? It seems there are comments that point to Mosfets burning out on their own. Is that a pretty well known issue?
So, next option is to replace the entire Master inverter board. But I've seen discussion that both master and slave should be replaced at the same time. And it is actually hard to find just the master at a reasonable price. So I am considering buying a master/slave set of inverter boards. It's kind of expensive, so the question is whether experts here think that is a reasonable way to go? And might there be other gotchas that I should check first so I don't just blow out the "new" inverter board(s) that I install? Are there conditions outside the inverter boards that can destroy the inverters, like short or overvoltage supplies? Basically, my question is whether most inverter board failures are typically local to the inverter board(s)?
This forum is a great resource. If/when I get something actually resolved, I will post details of the results.
F
As for TV symptoms...there is no backlight, but there is an image on the screen when shining a flashlight on it with Menu selected. The backlight does not flash when the TV is turned on. I can't tell if there is working sound since I can't easily select an input, but I expect there is no sound.
All this seems to point to classic inverter board failure, and I am considering options to fix it. Just changing the caps seems like it won't do the job if a Mosfet and an IC are blown. Is that the general wisdom here? Putting in a "kit" to replace the mosfets and the IC is a real hassle (especially for the IC). And it may not fix the root cause that blew them in the first place, which may have been a bad Capacitor. And are there reasons other than a bad capacitor that might blow a mosfet and the IC? It seems there are comments that point to Mosfets burning out on their own. Is that a pretty well known issue?
So, next option is to replace the entire Master inverter board. But I've seen discussion that both master and slave should be replaced at the same time. And it is actually hard to find just the master at a reasonable price. So I am considering buying a master/slave set of inverter boards. It's kind of expensive, so the question is whether experts here think that is a reasonable way to go? And might there be other gotchas that I should check first so I don't just blow out the "new" inverter board(s) that I install? Are there conditions outside the inverter boards that can destroy the inverters, like short or overvoltage supplies? Basically, my question is whether most inverter board failures are typically local to the inverter board(s)?
This forum is a great resource. If/when I get something actually resolved, I will post details of the results.
F
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