Old CRT monitor shows scan lines near bottom on the monitor

[loninappleton]

I have a very old 19 in CRT monitor I don't want to give up. But it has developed some sort of visible scanling issue
at bottom of screen. I should expect imminent failure but the Windows area when OS is loaded is stable and shows no
problems. It's a KDS and it's adjustment buttons are worn out as well. I've been able to change the vertical and horizontal to shrink the screen out of the problem area but that does not seem to be a permanent fix. I'm not going to open it and try to adjust the yoke or anything. I just wondered if the problem was common.

[davexnet]

I have a very old 19 in CRT monitor I don't want to give up. But it has developed some sort of visible scanling issue
at bottom of screen. I should expect imminent failure but the Windows area when OS is loaded is stable and shows no
problems. It's a KDS and it's adjustment buttons are worn out as well. I've been able to change the vertical and horizontal to shrink the screen out of the problem area but that does not seem to be a permanent fix. I'm not going to open it and try to adjust the yoke or anything. I just wondered if the problem was common.

Do some research on the exact model name. If it's a well known problem, you may find some help.

I had a Samsung monitor that developed an issue, a few minutes research I found it was common problem and that somebody
had developed a kit to replace some of the electronics. (about $15 on Amazon)
About 90 minutes work to open it, some soldering, close it back up -
it lasted another 5 years

[loninappleton]

Thanks for answering. Yes it could be a board problem inside but I am not skilled in working with things
like schematics. My old users manual says KDS 19" XF-9bi just like that and "Xtreme Flat on the user guide cover.
There is a site listed called www.kdsusa.com. Hard to say if it's even still going. This CRT has been a tank and
running for 20 years or so (outlasting Office Depot where I got it.)

[loninappleton]

Dave I did a bit of thinking it through. There is a possibility that using some thin magnets (like those for business cards to put on the fridge) caused the problem. The front of the KDS has a lot of deep scuffs and I put a piece of cardboard with those magnets across the front at bottom. I shifted the carboard covering down a bit and the KDS has returned to stability. It may have had a gauzing effect but I don't know if that is a word or not. Will see if it remains stable now.

[thecoalman]

I recall there being a degaussing option in the menu on my Sony Trinitron.... 20 years ago. LOL

I'm usually not one to recommend getting rid of something that works but with the quality of new monitors and the power savings it just makes sense. You'll probably save enough on not powering that nuclear reactor in one or two years to pay for new monitor.

[loninappleton]

I recall there being a degaussing option in the menu on my Sony Trinitron.... 20 years ago. LOL

I'm usually not one to recommend getting rid of something that works but with the quality of new monitors and the power savings it just makes sense. You'll probably save enough on not powering that nuclear reactor in one or two years to pay for new monitor.

Heh. There's a degauzer on this one as well and I poke that button once in a while. It had no effect on the
lower screen random scan lines. Grey shell 5 x 4 LCDs are still available on the used market. I watch the pricing on those regularly.

Moving those magnets seems to have done it. Good as new again.

[davexnet]

Moving those magnets seems to have done it. Good as new again.

Hi Lon - good catch. My old Sony & Samsung CRT's didn't last more that about 10 years, you're
doing well with yours

[loninappleton]

Moving those magnets seems to have done it. Good as new again.

Hi Lon - good catch. My old Sony & Samsung CRT's didn't last more that about 10 years, you're
doing well with yours

Dave, you've been a great help on many subjects. I don't know much about the KDS brand but I wanted
something with a flat screen. Office Depot had this one on deal for $80.00 USD in 2001. I was fortunate to get it up and down stairs a couple times with a two-wheeled hand cart.

These days, the movers would have to do it.

[loninappleton]

The problem is not fixed with removal of the carboard mask described. I am back to wire jiggling. No need to
respond, just saying that what I thought was the problem failed. I'm thinking it's at a plug end into the
motherboard. I tightend things up and the problem is past again for now. It's very old stuff and has had a lot of action over the years plugging and replugging. But I never see any solder breaks inspecting the motherboard.

[thecoalman]

If you think it's solder related I fixed a mobo on a LED TV once by baking it. Put it on a baking sheet with some cardboard. Think it was 375F for ten minutes. Used a toaster oven outside because you will get a little smell. Then I cracked the oven door a little to let most of the heat out and closed it back up to let it cool slowly for about 20 minutes.

It was spike the ball moment when it worked. TV lasted another 4 or 5 years.

[loninappleton]

Thanks for answering. Reminds me of things I've seen on the derbauer podcast with Roman Hartung-- or reballing techniques. But the problem is I don't know what the cause is for sure. I don't know how graphics chips (this is an onboard graphics motherboard) interact with CRTs so it's a troubleshooting problem yet.

[davexnet]

I once found a fault (bad solder joint) on a Sony monitor by
lightly tapping sections of the boards with a plastic chopstick
until I could see it affect the intermittent problem on the screen.
Turned out to be a bad connection on the small board that
plugged into the back of the picture tube

In your case, it might be more likely to be a worn component
on one of the boards. Perhaps you can seek some advice in an eletronics repair forum

[loninappleton]

I have gone a little further on this. It's not a new problem so I tried an adapter I bought for the other DVI-D 15 pin socket for newer screens after putting off trying it. This was the second one I got because there's several different pins on various of the DVI D and DVDI- shape connectors and I got the wrong one the first time because I wasn't watching for such a difference. I plugged that into the mb and the VGA into that. Everything was dead-- a blank screen and the monitor power light on the front was flashing-- some sort of Will Robinson alert I suppose.

I replugged everything without the VGA adapter and things are nominally back to normal.

I did notice one other thing in all this: the scan lines are definitely generated at the system level when the BIOS is setting up on the black screen before the OS loads and are (I guess) have become always present at startup. Windows is not effected unless the scan lines creep up the screen. I don't know how layers of video work either.

So it might be BIOS problem? No idea.

As to the DVI-D adapter, the socket is located directly below the VGA so it looked like it should be connecting the same needed pins. I don't know if there's a BIOS setting for this-- or how to look it up.