Monitor trouble

April 10, 2005 2:36 PM

My 3 year-old CRT monitor has begun to flood yellow-ish, seemingly randomly. After much troubleshooting, I've found that I can temporarily fix it by whacking the side of the monitor like Fonzie used to do to the jukebox. What the heck is going on with my monitor?
posted by danny boy to computers & internet (20 comments total)

Loose connection.

DO NOT TRY TO OPEN THE MONITOR TO FIX IT. CRT MONITORS RETAIN HIGH VOLTAGES EVEN AFTER BEING SHUT OFF, CAPABLE OF CAUSING FATAL SHOCKS.

I remember having this problem years ago. While thumping the monitor or tugging on the monitor's cable can help, basically, it's time to get a new monitor. (As repair is probably more expensive then replacement.)

In any case, do you try to repair it yourself.
posted by orthogonality at 2:48 PM on April 10, 2005

Your monitor is breaking, you should plan on getting a repair or replacement. If it's yellow, the problem is the blue isn't displaying. This may be as simple as a loose connection.
posted by Nelson at 2:48 PM on April 10, 2005

s/In any case, do you try to repair it yourself./In any case, do not try to repair it yourself.
posted by orthogonality at 2:51 PM on April 10, 2005

My impression is that nine times out of ten, this problem can be solved by unplugging the monitor, clearing out the gunk in the plug and the receptacle (compressed air should do the trick, or hell, even just blowing on the fool thing), and plugging it back in. Failing that, buy a new monitor cord before you buy a new monitor — it's possible the cable got pinched or something over the years.

It's possible, of course, that there's some internal connection that's gone bad, in which case you'll have to replace the whole monitor or take it into the shop (cf. orthogonality's sage advice.) But why not try the quick fixes first?
posted by Johnny Assay at 2:57 PM on April 10, 2005

In any case, do not try to repair it yourself.

Scaremongering. Learn how to discharge it, and poke around for loose connections.
posted by Kwantsar at 3:04 PM on April 10, 2005

nine times out of ten, this problem can be solved by unplugging the monitor, clearing out the gunk in the plug and the receptacle

In many cases, there is no receptacle to clean -- the output cable is hardwired to the unit. At any rate, I should hope he tried the cable before he started whacking things.

Scaremongering. Learn how to discharge it

Unless you can teach him how to discharge it, I'd say orthogonality's got the better advice.
posted by jjg at 3:14 PM on April 10, 2005

The video-to-CPU cable is hardwired, but the power cord can be pulled out.



I just removed the power cord and blew on it. Whee! We'll see if that works. I guess step 2 is to get some compressed air and blow it all around the place. Frankly, whacking on things is much more satisfying.

(update after preview: getting the yellows again)
posted by danny boy at 3:24 PM on April 10, 2005

The cord in question is the cord connecting your CRT to the computer, not the power cord.
posted by jjg at 3:28 PM on April 10, 2005

The cord in question is the cord connecting your CRT to the computer, not the power cord.

That's what I figured. Damn this sucks, I have no $ for a new monitor.
posted by danny boy at 3:56 PM on April 10, 2005

Blow out the socket of your video card as well. Look at the end of the video cable and make sure no pins are bent over or missing, you should see 15. This is probably not your problem, though, considering that hitting the side of the monitor sometimes corrects the issue, but it's worth taking a look.
posted by odinsdream at 3:57 PM on April 10, 2005

The connection is going. It will die soon!
Look around, you may be able to find a cheap used CRT at a used computer store.
posted by defcom1 at 4:12 PM on April 10, 2005

Don't CRTs grow on trees now? Check out the free postings in Craigslist, other freecycle listings near you, and local universities for any unwanted cruft - they come up all the time. (I don't know where you are, but I can't walk to class without tripping on one). You shouldn't have to buy one new for general use.
posted by whatzit at 4:28 PM on April 10, 2005

I've been in this situation. It will last for a while, maybe even a year. But hitting it will eventually break some other really important solder joint, and it will go dead.

(OTOH, on my work computer, this happens because of a poor connection on between the laptop and the monitor, and no amount of hitting it would have an effect.)
posted by smackfu at 4:53 PM on April 10, 2005

Unless you can teach him how to discharge it, I'd say orthogonality's got the better advice.

I would be shocked (hey hey!) if Danny Boy could not do this repair safely. The library may have a nice, detailed book on do-it-yourself TV and monitor repair. If he can't be troubled to go to the library, I found that a google on the keywords "discharge anode repair" turns up decent links.

One could also simply leave their monitor off and unplugged for a few weeks if they are especially risk-averse. By then the charge should drain out of the capacitors.

I was also under the impression that many modern monitors discharge the anode automatically. That's no reason to assume that one's own does, though.
posted by tss at 5:09 PM on April 10, 2005

I think modern CRT-containing equipment does usually contain bleeder resistors (to discharge things), but as tss says you shouldn't assume that your monitor has these or that they're working. Always discharge the big capacitors and the HT before working on stuff.

Piggybacking on danny boy's question: I have a monitor with a similar problem, except it's the green channel that goes out, and whacking it usually doesn't help. Anyone know what the relative likelihood is of it being a loose connection vs. a dying tube? When the electron guns fail, do they fail individually or all at once? It's a middle-aged Trinitron.
posted by hattifattener at 9:55 PM on April 10, 2005

it's a loose connection ... and to those who question orthogonality's advice not to mess with the insides of the monitor, i have a question - just how many places do you know of that bother with fixing them? ... a lot of computer repair places won't touch monitor repair

i actually built the computer i'm using to read this ... and i won't have anything to do with monitor repair ... it's too dangerous
posted by pyramid termite at 10:45 PM on April 10, 2005

When TV's were young, and they were all too big to drag into the shop, a man came to your house and fixed them. That guy always had huge ugly burn scars in pairs on his arms, one where the current went in and the other side where it went out. Those guys did it for a living and presumably knew how to discharge them, although one could also assume they had no respect for electricity. They all had the scars, though.
posted by unrepentanthippie at 5:09 AM on April 11, 2005

In principal I agree that AskMe is full of scaremongers. In this case however, unless it is a very high end monitor, it just isn't worth opening up.

If you want to know how to do it properly, consult the Sci.Electronics.Repair FAQ on CRTs.

Assuming it is a bad connection... If hitting it helps the problem must be near (or within) the monitors body. Playing with the connector at the video card end isn't likely to help. (It is so easy you might as well do it anyway, but...)
posted by Chuckles at 6:20 AM on April 11, 2005

I'm a big believer in tinkering and fixing yourself and while I think a hobbyist can mess about inside a monitor safely I also think that sending someone who's never held a soldering iron in to do such a thing is pointless and dangerous.

I also think looking in craigslist is the way to go, and you might also consider posting in the WANTED section. You can mention you've always depended on the kindness of strangers or offer something in trade. CRTs are plentiful - I have two in my basement waiting for the next needy soul who twangs my heartstrings. Someone will make you a cheap/free deal.

Hell, mention the flaky one and offer it in the trade - perhaps there's someone with some spares who'd like an excuse to go looking for a loose solder joint.
posted by phearlez at 8:47 AM on April 11, 2005

If you're determined to do it yourself here's some links

An older newsgroup posting, a sci.electronic.repair FAQ, and
some basic electronic troubleshooting advice

Please note that if you own a soldering iron and decide to do this, some danger exists from stored current even if you take precautions to insulate yourself. I have a screwdriver with a notch 1/3 the shaft width missing from it, courtesy of an A/C arc. Read carefully all instructions about discharging the capacitors if necessary.
posted by phearlez at 9:01 AM on April 11, 2005