The screen is blue but nothing shows for tv or dvr

If your TV comes up blue and then does not respond to any button, especially if it doesn't respond to the power off then it definitely has a bad main board.

if it responds to the power off main button, but none of the other buttons has any effect on it then it may have a bad power supply, but it is about just as likely, if not a bit more, to still have a bad main board.

You can try flipping through the inputs with the INPUT button on either the unit or the remote to see if you can get it to produce sound (when on a channel / input with signal). It's a blind operation that takes some effort, but if you get it to produce sound that's a sure indication the problem is NOT in the power supply.

Short of that you need to to open the TV and measure the outputs of the PSU to rule it out, leaving out the main board and, eventually, the T-CON if the TV has one ( I did not check if your model does as it won't help me much even if I know it).

Sorry I can't be more specific, but I doubt anyone can.

Hope this helps.

Bobby
@ coppelltvrepair.com

Hi Mike,
If your TV is more than 4 years old cost of repairs will probably be more than a new or refurbished replacement.
Here's something to try:
If your LCD TV or monitor has stopped working, or is displaying one of the following symptoms, then it's a candidate for some new capacitors
- Flickering screen
- Screen image disappears after several seconds
- Dim screen
- Slow start
- Power LED on, but no picture
- Unusual colors and/or lines
The primary cause of LCD TV and monitor failure is caused by faulty capacitors. You can examine the capacitors in your LCD TV or monitor and actually see if they are bad.
If they appear bulged on top, then they need to be replaced.
New capacitors will solve a host of problems in LCD monitors and TV's and will extend the life of your monitor or TV by several years.
Check the cables, connectors and connections.
Take it to a repair shop.
https://www.youtube.com/watch?v=TR2iWN6b-LY