I need a drawing / picture of connections to the main psu board

Fault at its main digital board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electro-medical.blogspot.com/
http://electronicshelponline.blogspot.com/
In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Pull up older posts. http://electronicshelponline.blogspot.com/ . In most cases the main board replacement should need a firmware update too.

Hello Donald the first thing I would like to Know what the model number of your TV is. But that's ok if you have a external power supply you could try this .Make Shure your TV is not pug In to the Ac outlet. We are going to see if you have a short or a load on your 12v line. Ok you wont to unplug the 12v source from the power supply board. Fine out what pin is the 12v's. Connect your external power source to that pin, apply the 12v and see if it is drawing to much current. If so check the boards for any very hot items. If you have a problem on the 12v line. This will find the part that is loading it down. This is the old way of finding a load on a power source. I hope this will help some. P.S make Shure there is no AC connect to the TV as you do this test and you have the plug off of the power supply board before using the external power source.

Hi.

Check if there is on screen display (there should be none) and make sure that the problem occur with all inputs.

The problem is either defective PSU or defective inverter board. A bad main controller board or LCD panel can give the same problem but it is not common. Testing is done tracking voltage from PSU to inverter and LCD panel.

Here basic troubleshooting.

If the problem is not the connection, then it is usually the inverter not getting powered. In that case PSU, main controller board and inverter must be tested. Here general explanation of testing involved: How to test an LCD TV or monitor PSU and inverter.

Regards.

Ginko

Hi.

First check all the video connections at t back. Test using different connections (e.g. SCART and HDMI or AV cables), check if there is OSD menu. Here basic troubleshooting.

If the problem is not the connection, then it is usually the inverter not getting powered. In that case PSU, main controller board and inverter must be tested. Here general explanation of testing involved: How to test an LCD TV or monitor PSU and inverter.

Regards.

Ginko

Hi.

If there is sound but no picture, screen is completely dark and the picture is occasionally flashing, then the fault is likely a faulty inverter. In some case a faulty controller board or a defective PSU can cause the same problem.

I summarized the problem here:My LCD TV has sound but no picture.

I posted general procedure to test inverter, PSU and controller board on LCD here : How to test an LCD TV or monitor PSU and inverter.

If screen is not dark, but has blacklight or noise things are different. In that case check connection cables first. Parts that may be defective are main controller board, terminal circuit and tuner board.

Protron parts are available using the link below. Ensure that parts are compatible with your model before purchasing.

ShopJimmy - Protron Parts.

Regards.

take out the psu completely from the cpu/tower, plug in the power cord,if there is a switch on the psu turn it on, next locate the main power connector (24pin) and find green wire,take a piece of wire and insert it into the green wire connector,next touch the other end of the wire to the psu outer case or a black wire on the main connector,if all is well the psu will turn on,if you have a dc voltage tester check the voltages on the red and black wires on molex connector...5vdc,yellow and black...12vdc.if ok look at the main board and inspect the capacitors to see if they are swollen, if ok
replace psu and disconnect hdd,cd/dvd,floppy ect from main board only leave memory,processor and video, power on if ok shut off and reconnect hdd, power on, if ok shutoff and connect floppy, if ok power off and connect cd/dvd drive.during this testing you will know what is bad.let me know how it turns out.email; [email protected]

Yup sounds like a classic SMPS fault OK, probably the "Chopper" transistor? but could also be the controller, the best way is to get a new PSU, but check to see if PSU is OK without a "Load" if it is then it is NOT your PSU,and the fault is elsewhere and is shutting it down. Usually it is something drawing a lot of current.. often in the Horizontal section, but not always.. GL

it can be the wire getting short from the main board towards the power supply board which helps to get the picture that needs to be checked and replaced to get the proper picture.