(Please click on high lighted words) this is my sample may not be the same model but doesn't matter the technology is the same.
Would like for you to take your meter and place it on DC voltage, start at the power supply the positive end on VS, Then VA and the negative wire to the panel this is the best ground. Turn on and see if the voltage is present at the VS, VA, V-scan, According to the Label. if a voltage is missing remove each plug from the power supply to make sure they are not holding down the voltage, If you don't find one that's trying to climb, or shows close to what it should be, another method is to locate a short circuit place meter on ohms or beep test follow same procedure no voltage should be shorted to ground. And this is the problem. You can unplug each board one at a time, Starting with the Y-SUS then the Z-SUS.
Friend this is a very common problem with plasma. Within the power supply the capacitors
Start to fail and the way you can tell is to check them visually for swelling or expanding of the top.
It will be easy to see the bad caps will not be as flat on the top as the good ones
Normally the parts for this unit is a kit Y-SUSTAIN AND Z-SUSTAIN BOARD, this is what most manufacturers would want you to do, purchase them. But go to high lighted words and go through all the voltage checks to find the bad part, here is also a chart that should help a lot, also this is a picture that will help with identity.
Well Good luck friend, and if my efforts are appreciated, feedback and a bonus will be appreciated
Thanks Simplified click here