I was surprised to see AC voltages coming from pin 13, could this be the issue a bad power supply? What would you recommend changing the Power Supply, Mother Board or both?

If you have checked and confirmed that the voltage at the PS_ON pin does not change when hitting the power button, it is possible that the main board (756TXBCB2K013) is the faulty component. The main board is responsible for sending the signal to turn on the power supply board (ADTVA2419XYG). You may want to try disconnecting the main board from the power supply board and then pressing the power button. If the voltage at the PS_ON pin changes, then it confirms that the main board is faulty. If there is still no change in voltage, then it is possible that the power supply board is faulty. Alternatively, you can also try checking the capacitors on both boards for any signs of bulging or leaking, as faulty capacitors can sometimes cause issues with power supply.

I'm sorry, but I am not able to provide specific service manuals or schematic diagrams for specific products. I would recommend contacting the manufacturer or a authorized service center for assistance with obtaining a service manual or schematic diagram for your specific device. They may be able to provide you with the information you need or point you in the direction of a resource where you can find it.
In general, when troubleshooting issues with a power supply, it can be helpful to check the voltages at various points in the circuit to determine where the problem is occurring. If you are not getting the expected voltages at certain points in the circuit, it may indicate a problem with the power supply or with components downstream of the power supply. You can use a multimeter to measure the voltages and compare them to the values specified in the service manual or schematic diagram to help diagnose the issue.

First off 3.2 is the correct voltage for the PSON so we know the main board is sending the signal back to the power supply instructing it to come out of sleep mode and go to work, if your other power supply voltages are ok then you can rule out the power board. A gut feeling is you have a bad main board but its only a guess without doing some testing on the TV...you said you don't have sound, is that because you can't tell what input the set is on?...also have you tried the flashlight test?

output voltage for 13 amp

Pin Name Color Description
1 3.3V Orange +3.3 VDC
2 3.3V Orange +3.3 VDC
3 COM Black Ground
4 5V Red +5 VDC
5 COM Black Ground
6 5V Red +5 VDC
7 COM Black Ground
8 PWR_OK Gray Power Ok (is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation)
9 5VSB Purple +5 VDC Standby Voltage (max 10mA)
10 12V Yellow +12 VDC
11 3.3V Orange +3.3 VDC
12 -12V Blue -12 VDC
13 COM Black Ground
14 /PS_ON Green Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.
15 COM Black Ground
16 COM Black Ground
17 COM Black Ground
18 -5V White -5 VDC
19 5V Red +5 VDC
20 5V Red +5 VDC

/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply's /PSON input to ground, thereby switching the power supply to full-on condition.
18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300W configurations 16 AWG is recommended.
There are several ATX variants.
Hope this helps.
If this helps you resolve your problem, please
consider giving me a rating of 4.It will help me as well. Thank you.

Well here is a way to check your power supply, on your hard drive connector using your volt meter and measuring from ground. this would be using one of two middle connectors it should measure +5 VDC on the red wire and + 12 VDC on the yellow wire. If these voltages are good then we got to see if the power supply is producing the -12VDC voltage. This voltage is ussed by the syustemboard on pin 14 of a 24 pin power supply. I would recommend not having your system board plugged in while measuring these votlages, but the power supply may need a load, I would plug in the cdrom.. Below are a couple of picture to explain this and a link to a website that has this documented.

http://www.playtool.com/pages/psuconnectors/connectors.html

The 24 pin main power connector was added in ATX12V 2.0 to provide extra power needed by PCI Express slots. The older 20 pin main power cable only has one 12 volt line. The new 24 pin connector added one line apiece for ground, 3.3, 5, and 12 volts. The extra pins made the auxiliary power cable unnecessary so most ATX12V 2.x power supplies don't have them. The 24 pin connector is polarized so it can only be plugged in pointing in the correct direction.
Pinout Pins 1 through 12 Pins 13 through 24 Description Wire color Pin number Pin number Wire color Description +3.3 volts orange 1 13 orange +3.3 volts +3.3 volts orange 2 14 blue -12 volts ground black 3 15 black ground +5 volts red 4 16 green PS_ON# ground black 5 17 black ground +5 volts red 6 18 black ground ground black 7 19 black ground PWR_OK gray 8 20 white -5 volts (optional) VSB +5 volts purple 9 21 red +5 volts +12 volts yellow 10 22 red +5 volts +12 volts yellow 11 23 red +5 volts +3.3 volts orange 12 24 black ground
Good Luck I hope this helps.

Since there is voltage coming from the power supply try your printer in a known working ac outlet.

If your still not getting power then that means the main board inside of the printer is bad.

Yes, it does.
More than likely Electrolytic Capacitors, have gone bad in the power supply.

Electrolytic Capacitors are used in the Input, and Output stage of the HiPro power supply, as Filters.

In the Input stage they filter the incoming AC voltage.
In the Output stage they filter the rectified AC.

(AC is rectified into DC. The capacitors are filtering DC at this point.
AC = Alternating Current
DC = Direct Current
A flashlight battery is an example of stored DC)

The HiPro power supply you have produces three main voltages. Three voltage Rails.
A.3.3 Volts
B.5 Volts
C.12 Volts

When Electrolytic Capacitors go bad, or are failing, there is a weak voltage rail.

HiPro power supply's are cheaply mad.
1.The wiring is too small. (The gauge of the wire is below standards)

2.The Electrolytic Capacitors are of low quality.

3.The rectifier bridge has cheap diodes, and too small of a heatsink.

I could go on, and on.

When you have a power supply with a weak voltage rail, there is not enough power for the Processor.

1.ALL the lights use less than 1 Watt.
2.EACH fan uses 2 to 3 Watts.
3.A typical Processor can use 55 to 125 Watts!
[Depends on what processor it is.

This is why lights - light, and sometimes fan's will spin, but the computer won't run.
Not enough power for the Processor.

Solution?
Replace the power supply.

Viewing this link,

http://www.pcmarketusa.com/product_view.aspx?product_ID=18498

,you can see the HiPro D3057FR3 power supply has just the usual ATX shape, and size.
The ATX 'Form Factor' power supply, is used in approximately 90 percent of computer towers.

[Form Factor usually denotes towards a motherboard. An ATX form factor motherboard is 9.6 inches by 12 inches. Form Factor means the size, and shape.
The Form Factor designation, has been used towards certain hardware parts in a computer, as well as the computer case, but this is erroneously used. It does make it easier to identify with, though. That's why I used it here]

Point I'm getting to?
1.See if you have another Known, GOOD, ATX power supply to use for a test. Test my statements above before you go out, and buy another power supply.

Do you have another computer that has a good power supply, but may have other issues, that you can borrow the power supply out of, to use for a test?

Another thing. This manufacturer overstates the actual rated Wattage. The actual wattage is more like 70 percent of what is stated.
They state 300 Watts - Maximum, but in reality it is more like 210 Watts.

It is for this reason, and the reason that components used in the above power supply are cheap, that I would recommend buying a different power supply, than buying another HiPro.

(Therefore,.NO, I do not recommend the one in the link above, as a direct replacement)

What power supply that fits your needs would I recommend, that is a decent quality power supply, and won't break the bank?

This one,

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4675269&CatId=106

OCZ StealthXStream 400 Watt.
Why?
Because it has 80 percent of the true rated wattage.
320 Watts actual.
Because it is reliable.
Because it has all the power cables you need.
Because it is $28 USD after the rebate.

I'm sticking my neck out recommending a particular power supply here, as this goes against our TOS, but if you have no background in this area, how are you going to know what to look for?

I am not recommending the website. But I have used them repeatedly, and always to my satifaction.

Any questions?

I believe it is a Back Light failure. Either because of a bad Ballast, a Power Supply, or a bad Lamp that is not replaceable. If it is a bad Ballast or Power Supply they are replaceable. Checking the Voltage from the Power Supply for the Ballast will tell if the Power Supply is bad. It should read around 250V to 300V.
If the Voltage is there, the LCD Panel will probably need to be replaced. I recommend a professional to evaluate it to be sure.
I hope this helps,
Skyassoc

ATX Version 1.2 - 20 wire motherboard connector Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Pin 9 Pin 10 3.3V 3.3V Gnd 5V Gnd 5V Gnd P_OK 5VSB 12V Oran Oran Blk Red Blk Red Blk Gray Purp Yell Oran Blue Blk Green Blk Blk Blk White Red Red 3.3V -12V Gnd P_ON Gnd Gnd Gnd -5V 5V 5V Pin 11 Pin 12 Pin 13 Pin 14 Pin 15 Pin 16 Pin 17 Pin 18 Pin 19 Pin 20 The color scheme used for the voltages in the 20 pin connector holds for the other ATX standard power supply connectors. However, brand name manufacturers often build proprietary power supplies or make up their own color coding, so I wouldn't throw out a power supply that supplies 5V where you think it should supply 3.3V. It's more likely a proprietary design than a failure.