Hello,
It was a pleasure talking to you on the phone. As a recap I you have a customers flat screen tv at your shop because they brought it in to you because the TV would not turn on. You have the TV, and it wont turn on even manually, you test the out put amps and all seem to be normal.
Here is my advice first, is sense the customer did not drop off the remote, it is possible, that if you get the remote from the customer and make sure there is good batteries in it, is take out batteries and replace them with new batteries and try to turn it on, if this still does not work, then this is most likely what it is and needs to be replaced, I am 99% sure if after trying the remote with new batteries still does not turn on the set, then you have a blown capacitor. If you replace the capacitor, this will most likely solve the problem. capacitors get what we call swollen, and that is cause by surges, storms shutting off power etc,,,, So, again, if remote does not work after trying this, next step is try replacing the capacitor. Let me know, mike from fixya.