Saisho tv sleep mode

Generally, its the Y-Sus board (check for burnt diode, next to heat sink with possibly a burnt (3-prong transistor on heat-sinks) and the large chip that is soldered flat on the board and that large IC Chip will need to be replaced and they are very specific to your model.) There is affordable service on Ebay that you send your board in and they send you one back as long as yours hasn't been worked on.
Prior to this check all fuses as the Main Power Board is also a fault of most Plasma tv's.
I would find someone on www.kijiji.com in your local area to assist you.
An easier solution perhaps is to find an identical model on kijiji perhaps that the screen is broken and keep all the electronics from it and recycle the screen - most people throw them in trash but not environmentally friendly.
You can fix this problem yourself typically from 10.00 to 80 to 120.00 but you may have to order and wait for parts.
or have a repair shop do it for $120 to $200 if reasonable.

This may or may not be a solution to your problem but is typical.
Future preventive measures may be to have a surge protector on your equipment, cheap ones can be found at the dollar store or a cheap electronics place. Most are built into power bars.
Since solder is now lead free it's properties lead it to failure eventually from heating and cooling, contracting and expanding, this in turn will make things arc and distort signals which swells capacitors trying to filter it and eventually something gives. I think it's built in, lmfao, part of the Chinese Conspiracy perhaps to drive us all nuts and make us pay through the nose for electronics that fail shortly after warranty expires.
One crazier solution is to build cooling fans to cool the Hot areas (noticeable upon close inspection where motherboards turn brown from the heat and sometimes warp.

Hope this helps but unless you can tinker with this stuff, have the patience and time as well as the storage area to lay things around...
well, there are youtube videos to guide you.
Try searching there for the DIY in ya.

East Coast Canada Rocks!
Good Luck.