Trying to revive a dead Vizio 42inch LCD TV.
Looking at the PS revealed no swollen caps.
Here is what is happening.
Set has been worked on, had the D907 removed.
I replaced it, maybe not right ?? with a double diode from some IBM AT supply.
First power up, the 5V jumpos up and down only to 3 v then to 0.
So I looked on mainboard, and yanked the cable going from the right side input block and now 5V came back at a steady 5.21V.
However no other power, punching on button no soap. No 12V or 24V come up.
Tried jumping the PS_ON to 5V and this only turns on the relay which appears to kill the AC to the 165V bridge rectifier. 5V remains on however.
There are A and B lines, measure 0V. Do these need 5V or some other voltage or some signal coming from the mainboard to cause the supply to turn on other voltages? With the PS out of the set and powered on, it only still has the 5V running.
Now I plugged back the right side input block connector plug it in and now it still has 5V coming out but nothing else.
I am noticing the main processor gets very hot after 10 minutes or so.
So suspecting bad mainboard? However without all power from PS how can one know if the lack of 12V is cause of problems.
All fuses on mainboard check ok, and I can spot 3.3V 2.5V etc from the mainboard regulators ok.
Obvoiusly unable to go any further.
Nobody except maybe one person on Ebay has a replacement P/S for this.
I would just love to know what I should be seeing coming from the mainboard, and/or if the PS should be supplying all normal voltages.
I can see a 14 pin and an 16 pin IC on the foil side of the board, but nobody has a manual for the PS so I have no idea what these chips are and what voltages they should have.
I carefully measured them with the PS out of the TV, and get no voltages on them at all. I am getting the 165V from the Primary to the 2 transistors that drive the larger switching supply. I can tell it is what is not running, and it handles both the 12 and 24 volt supplies.
My thought is that this IC601 has failed, as I cannot even see the number on the chip, as if it overheated and burned them off.
I would just recap the supply if it would at least come on long enough to test out the rest of the set.
I can see it is a nice set, offering a host of stuff and 120HZ picture etc.
It's missing the back cover and stand but I figire on building a cardboard cover painted black and make a stand out of plywood if needed, or just buy a wall mount. But have to see if it works first.
Ok so any help is appreciated, or if you have any advice on how to test the supply. People seem to indicate that getting any type of service manual is close to impossible. I certainly see no hope for that.
Elektrotanya is what someone advised, I haven't just checked it yet but I will.
Looking at the PS revealed no swollen caps.
Here is what is happening.
Set has been worked on, had the D907 removed.
I replaced it, maybe not right ?? with a double diode from some IBM AT supply.
First power up, the 5V jumpos up and down only to 3 v then to 0.
So I looked on mainboard, and yanked the cable going from the right side input block and now 5V came back at a steady 5.21V.
However no other power, punching on button no soap. No 12V or 24V come up.
Tried jumping the PS_ON to 5V and this only turns on the relay which appears to kill the AC to the 165V bridge rectifier. 5V remains on however.
There are A and B lines, measure 0V. Do these need 5V or some other voltage or some signal coming from the mainboard to cause the supply to turn on other voltages? With the PS out of the set and powered on, it only still has the 5V running.
Now I plugged back the right side input block connector plug it in and now it still has 5V coming out but nothing else.
I am noticing the main processor gets very hot after 10 minutes or so.
So suspecting bad mainboard? However without all power from PS how can one know if the lack of 12V is cause of problems.
All fuses on mainboard check ok, and I can spot 3.3V 2.5V etc from the mainboard regulators ok.
Obvoiusly unable to go any further.
Nobody except maybe one person on Ebay has a replacement P/S for this.
I would just love to know what I should be seeing coming from the mainboard, and/or if the PS should be supplying all normal voltages.
I can see a 14 pin and an 16 pin IC on the foil side of the board, but nobody has a manual for the PS so I have no idea what these chips are and what voltages they should have.
I carefully measured them with the PS out of the TV, and get no voltages on them at all. I am getting the 165V from the Primary to the 2 transistors that drive the larger switching supply. I can tell it is what is not running, and it handles both the 12 and 24 volt supplies.
My thought is that this IC601 has failed, as I cannot even see the number on the chip, as if it overheated and burned them off.
I would just recap the supply if it would at least come on long enough to test out the rest of the set.
I can see it is a nice set, offering a host of stuff and 120HZ picture etc.
It's missing the back cover and stand but I figire on building a cardboard cover painted black and make a stand out of plywood if needed, or just buy a wall mount. But have to see if it works first.
Ok so any help is appreciated, or if you have any advice on how to test the supply. People seem to indicate that getting any type of service manual is close to impossible. I certainly see no hope for that.
Elektrotanya is what someone advised, I haven't just checked it yet but I will.
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