Re: Vizio VF552XVT Power Problem.
ok...I'll replace those resistors and see what that does....
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Re: Vizio VF552XVT Power Problem.
Unfortunately they are all fine. It's the string after the transistor connected to the cap + that is lower than they should be. By about 20%....
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Re: Vizio VF552XVT Power Problem.
I checked all the resistors in the area. If anything they've drifted down a bit, but nothing has gone up in value. The ones closest to the IC are spot on.
Do you think it could just be a bad filter cap at this point?
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Re: Vizio VF552XVT Power Problem.
ok thank you very much for your help. I'll post the findings when I have them....
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Re: Vizio VF552XVT Power Problem.
c819 is the filter cap. There is a small transistor and then a block of resistors that is connected from the positive side of the filter cap and then to pin 6 of IC800 after the resistors.
I'm not sure what to do from here.
Are you saying that the IC is bad? Or that I may have a bad resistor in that block?...Last edited by wadehavens; 08-22-2018, 10:19 PM.
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Re: Vizio VF552XVT Power Problem.
I think I found the IC. ICE2PCS02 is it I think....
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Re: Vizio VF552XVT Power Problem.
I'm not quite sure exactly what I'm looking for. I see a resistor network, and a couple of IC's but not sure which one is the PFC IC....
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Re: Vizio VF552XVT Power Problem.
Ok, so I did solder reflowing around the filter cap. The transistors and the ic's on the hot side seemed kinda cold. Now, it turns on and stays on. However, the voltage at the filter fluctuates between 316v and 330v depending on the video that's playing and how bright it is. I'm gonna monitor the voltage for a few hours and see what happens....
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Re: Vizio VF552XVT Power Problem.
Unfortunately the markings on the cap are on the side that is glued to the board. The bottom of the cap does have a 4XXv on it, but it's cut off to the point that I can't tell what it is.
YES, that is the same board that you linked to on Shop Jimmy....
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Re: Vizio VF552XVT Power Problem.
I tested the voltage at the filter cap.
162v off
305v on with CN3 disconnected, (half backlight)
304v on with CN2 disconnected, (full backlight)
305v and a quick drop to 157v when all connected. (supply shutdown)
No leaking when on before shutdown....
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Re: Vizio VF552XVT Power Problem.
The PS-ON voltage stays on when the power supply shuts off. About 3.3 volts.
I'm not sure where to test the voltage on the main filter cap since the cap is under the large heatsink. I've been testing the power supply mounted to the TV....
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Re: Vizio VF552XVT Power Problem.
Yes, thats the power supply....
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Re: Vizio VF552XVT Power Problem.
No...the 5v stays on but the rest of the power supply shuts down. But it seems to be triggered by the 24v rail since disconnecting half of the backlight will allow the supply to start up. So I suppose it could be anywhere in the power supply other than the 5v rail....
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Re: Vizio VF552XVT Power Problem.
I replaced the smaller caps. One was a 2.2 @ 50v and the other a 100 @ 50v. Neither made a difference. It still shuts down if both sides of the backlight is connected. The backlight brightness doesn't change a thing. It's for sure a problem with the 24v side, at least is seems that way, but other than replacing the big caps I'm not sure what else to do. Possibly the transistors on the 24v rail maybe?
If I leave it off for a day or so, it will turn on for about 40 minutes....Last edited by wadehavens; 08-21-2018, 11:10 PM.
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Re: Vizio VF552XVT Power Problem.
I unplugged CN3 and CN4 and the power supply works as it should. I then reconnected CN3 and half of the backlight works. Same result with CN4 only. Then reconnected both and the supply shuts off....
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Re: Vizio VF552XVT Power Problem.
Everything tests good. The entire power supply shuts off when both CN1 and CN2 is connected. If I unplug either one of them, the power supply works as normal. Of course, the back light does not come on when only CN2 is connected but does when only CN1 is connected....
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Re: Vizio VF552XVT Power Problem.
Here is a Pic of the back of the tv...
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Re: Vizio VF552XVT Power Problem.
Just a quick side note. The power supply will stay on with either cn1 or Cn2 connected, but not with both.
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Re: Vizio VF552XVT Power Problem.
Cn2 is the plug I can have disconnect....
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Re: Vizio VF552XVT Power Problem.
There is only one driver board.
Here a couple of pics.. Sorry if they suck my phone is a piece of garbage....
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