I have a 50 inch haier plasma screen is blue and sys no signal i am unable to change channel from the remote or the buttons on side of tv please help

Try to disconnect the set and a box if being used from power for a while and then power both back as either could cause this problem.

shorted main pcb assy

Replace your main pcb assy and it will fix your problem. I have had many come through our shop.

i had the same problem and i bought the new remote control and it did work at first i thought it was going to do the same thing but then i pushed the tv/use button and it worked perfectly.

Bad Capacitors in Power supply. IF doesnt help changing Capacitors Replace Power Supply Board

my tv just went to a blue screen one day. I can turn it on and then it will just remain on the blue screen. Any button (except the volume) I push on the remote comes up on the screen "no signal". What would you suggest? I have been reading about replacing a fuse or board? Most of those are on the 42 inch version---I have teh 37 inch version.

Well make sure it's on the right source, I have a 50 inch Samsung and when you're on the wrong channel it'll read no signal and you can't do anything. So make sure you have cable hooked up right and make sure it's on the right source or video channel first. I don't know but this might help.

If you have the 3 RCA jack cables connected to the input jacks on the TV press input on the remote until the picture appears.

try changing to other inputs and move the connection along with it

It sounds like a stuck button or switch. What happens when you hit the channel DOWN, does it still keep scrolling down?
Is this with or without the remote?
Have you tried it with the remote and or the TV?

Let me know whether you are changing the channels with the remote or the buttons on the tv and I can try to give you a couple more suggestions.
Mac =)