This is a Panasonic Plasma TV. Model number TCP42X5. When this TV came in my shop it only had stand by power. When I pushed the power on button and measured the VS input terminal on my Y-Sustain board, I noticed VS voltage only came up to about 1 volt before immediately shutting off. Seeing even the smallest voltage on my power supply secondary suggested it was probably Okay, so with the power off I used my resistance meter to measure the resistance between ground and my VS input terminal on the Y-Sustain board. I did not measure any low resistance shorts to ground, but nevertheless there was still a problem on the Y-Sustain board preventing the power supply from switching on due to a feedback loop from the Y-sustain board and the power supply. The problem was confirmed after I replaced the Y-Sustain board and the TV started working.. Sadly I damaged my new Y-Sustain board by attempting to re-seat my ribbon cables between the buffer board and the Plasma Display while the power was on. One of my viewers reminded me it might also be a good idea to discharge the larger capacitors on the Y and Z sustain board before re-attaching the cables. With the power off of course.