I just replace the power board in a Sanyo DP50747 TV work great. But of the bottom of my screen about 2 1/2 inch I counted about 23 horizontal black line running from one end of the screen to the oth

Could be the main board, power board or Tcon board, take your pick...only way to isolate what one is bad is use a multi meter and test the various power supply voltages and see what is missing or out of tolerance.

change ysus board

Try to change the Inverter board (Buffer board).

This tv problems are related to powering up the tv and sustancening the tv power source to the tv itself.Replaced the tv sub power supply board where the a/c power cord plug into it.Try website like Ebay.com to buy a whole new refurbish sub power supply board for the replacement.

Yes it is repairable. You will need to have the video board replaced. That line usually indicates an error in the video board.

The problems must be trouble shoots by the shop.The priced to trouble shoot and replacing boards should aroud $500-$600 dollars.

my Sanyo DP50747 plasma tv won't turn on. I tried plugging it up to another outlet, but still no power.

This is a Sanyo Vizon 50" plasma the model number is DP50747 .. hope this helps the website for this product is www.sanyoctv.com and the phone number is 1-800-877-5032

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. Pull up older posts.
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.

Just saw your post, I have all the parts you need to fix that TV. I if know what part you need I can help. 702-951-1313 ask for Lamont.