Mitsubishi CS 40503 TV

you didn't mentioned if it is a horizontal line but i think it is.
It seems that you have a faulty vertical I.C. that scan vertical line.Because you it is defective you've lost the vertical scanning thats why you have only a horizontal line on the screen.

You will confirm it by powering on the unit with your cable signal present.When the sound is present on every channel it is confirm that you have a problem on the vertical section. You must look for a qualified technician to solve the problem....

Do you have or are you using the original Mitsubishi remote for this?

SD TECH

no picture?do you see a white horizontal line in the mid?or black out?
its up to you if its really worth fixing. if its really old then ,i think its time to buy a new one, if not try comparing the cost.

You have trouble with the vertical deflection circuitry. Probably something in the driver circuit or power supply to the driver. Maybe even a cold solder joint since it comes up after a little warmup.

Could be any number of things, none of them easy to diagnose. Unless your a TV repairman it's probably not worth fixing. It will cost tou more in repairs than a new TV.

Your trouble is with the vertical deflection circuitry. You'll need to have it serviced by a professional.

that's a big problem. sometimes using the 0000 can unlock it but it's not 100 percent.try the trial and error.

there are bad solder connections on the vertical deflection IC resolder them and you will be fine

1. YOU WILL NEED TO CHANGE
2. Q6c2
3. Q291
4. D251
5. CHECK MOUNTING OF PIP-PCB TO MAIN-PCB

ok! you have defective vertical boost up! your defective parts is small capacitors or resistors! at vertical section!