The top 1/3 of the plasma display is reddish in color

Plasma is old technology and it is 16 years old and made in Mexico, the worst place for quality control. It is time for a new one, or at least an upgrade. Or you can get a board kit and take a chance on fixing it.

Samsung HPT5054X/XAA Service Manual

ManualsLib https://www.manualslib.com > ... > HPT5054X/XAA

View and Download Samsung HPT5054X/XAA service manual online. Plasma Display TV. HPT5054X/XAA plasma tv pdf manual download. Also for: Hpt4254x/xaa, ...

Boards for it.

https://www.google.com/search?q=Samsung+plasma+tv+model+HP-T5054+board+kit

If you wish to get some details; check the site linked here. Pull up older posts. https://electronicshelponline.blogspot.com/
Line, faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.
Screen-shots to defective LCD and Plasma panels are given. You can see and compare to that to your TVs', and can make sure about the fault to an extent.

assuming you gave checked the menu settings for the video out, I would say your plasma panel board may need to be replaced

If you wish to get some details; visit the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.
Search the site by type in the "BRAND NAME" of your device; (Exclude the model number), in the "Search box at the top right of the display window of the Homepage" to get gathered related posts

this is not an easy fix. the screen ,or the x or y screen drivers are bad .

adjust vscan  vs & va voltages on power supply, if not that drive pcb's are bad

I have a 21'' NEC TV Screen and it about 3 year old. the colour has gone to yellow and green color and the red etc

LG 700e
power suply is dad
resistanc is black not show it ohom
plz help

VS is vertical scan of course it is controlled by applying voltage, lower or higher you affect the scan, it appears as focus or sharpness, if it is outside the specifications listed on the back cover(inside) then it will not function properly. definitely get with samsung on this and get a ticket number so they can not just blow you off, if you have an extended warranty they might have to replace the tv as this sounds like it may be a tube issue not just a scan issue, also don't let the tech leave until the tv has warmed up and the image is either the way you like it of he stays.

Hi
I just bought a 42pc5d plasma tv it's an LG I bought it in Sept. 07 it started doing the exact same thing your talking about here the red glow type thing. Luckily for me and I hope in your case that the tv is under warranty, although if you know someone or even a repair place I don't think it would cost much to fix (just a guess but the guy told me that it was an easy fix so don't let them try to screw you). It really is a simple fix according to the tech. You need to adjust the voltage. He took the tv and watched it until he saw the red and adjusted the voltage and I had my tv back the next day. This was about a week ago and I haven't seen it since. I hope this helps and I hope you have a warranty. By the way LG comes with a 2 year manufacturer's warranty standard so if you didn't get an extended warranty from where you bought it if it's less than 2 years old call LG and they will arrange to have it fixed that's what I did. Here's the number 1-888-542-2623. Good luck.