I’m going to school for electrical engineering (haven’t had many engineering classes yet but I know the basics) and have been buying tools at home to tinker with. I got the idea that a broken television might be a great project to work on so I bought a 50" HP PL5060N plasma television that showed gibberish on the screen if anything at all. I had been using a 27" CRT I bought 10 years ago so it’d be a hell of a replacement. I fixed the original problem by replacing the y-sustain, y-drivers, and z-sustain boards but since, some other problems have revealed themselves.
The first problem showed up about an hour into using the television. There are two magenta vertical lines on the left side of the screen that show up best on blue or white backgrounds. It appears that the blue isn’t showing up on two columns of pixels. The repair manual suggests that it’s either the x-driver, control board, or tcp, the last of which isn’t replaceable at home. From the looks of it, if it was the control board, there would be regular lines across the screen so I’m leaning away from that for this issue. I fiddled with the ribbon cables going from the drivers to the panel while the tv was on to see if maybe it was a loose connection and moving it would affect the lines, but it didn’t affect them at all.
The other issues showed up after several hours of use. The second issue is that the screen occasionally dims. It’ll either flicker or stay dim, and goes back to bright immediately once what’s on the screen suddenly changes such as a scene cut. On this one, the manual says a dark display is an IPM fail on the z-sustain board but I doubt that since it’s intermittent. Maybe a loose connection or bad solder joint?
Thirdly, the tv occasionally makes a chirping sound like a cricket. I may try putting it on the stand with the cover off for a while to try to pinpoint it better, but with the cover on it sounds like it’s coming from near the center of the tv, about where the control board is. It doesn’t seem to happen at the same time as the dimming.
The last one I’m not sure if it’s a problem or not. Whenever whatever I’m watching goes black, it has a dim afterimage of whatever was on it before. It’ll stay on the screen for as long as the scene is black, but once something else appears on the screen, even just subtitles at the bottom of the screen, it all goes away. I watched a movie last night with a few parts where it’s black for a few seconds and it never went black. I’ve only noticed it on composite input (maybe simply because broadcast television rarely has moments when it’s completely black) and there’s no afterimage if I switch to an input with no signal. Also, the afterimage remains even when I bring up the menu, suggesting to me it’s some early stage of the signal processing. I’ve read that plasma televisions do have a bit of an afterimage at times, but it sounds a bit different than what I’ve got going on here. It also sometimes has red static on black parts of the screen.
So I was hoping there are some electrical engineers or tv repairmen who can help me out here. It seems likely that not all these problems are interrelated, but it seems unlikely that none of them are. I can get the x-driver board for about $20 so it’s probably worth a try for the two lines. The control board is about $40 so it’s not going to break the bank either, but I’d at least like to know there’s a significant chance that’s what’s causing the issue before getting it. Other than that, I’m out of ideas.
