What's wrong? My 20" monitor "clicks/flashes"
Posted 04 February 2003 - 05:17 PM
It is quite rare, but sometimes the monitor suddenly makes a clicking sound and the screen flashes. It happens very quickly so I can't tell if the whole screen is flashing or if it's just a few scanlines or what. I just hear the click and notices the bright, but very very quick flash of light. Then everything is normal again.
(Previously I asked on this forum why the monitor was generating a constant high frequency sound and was told that this propably was due to dying capacitors. However, I resolved the problem (the high pitch sound was very annoying) by simply changing the refresh frequency.)
Should I be worried? Should I start saving for a new monitor?
Posted 04 February 2003 - 07:45 PM
The clicking sound may be either (a) internal arcing, or ( a solenoid, like the click some monitors make when you change screen resolutions/refresh rates.
At any rate, the phenomenon you describe does not sound normal and may develop to become a fire hazard.
Anybody else care to add/delete/correct?
Posted 04 February 2003 - 08:41 PM
Anyway, you just described symptoms very similar to those that my monitor experiences, though perhaps you are experiencing them with greater frequency as it hadn't occurred to me that it is a problem.
Occasionally, a horizontal line will "flash" (accompanied by a brief "click" sound) across my monitor approximately 2/3 the way down the screen. Perhaps importantly, this flash is _always_ 2/3 the way down, it never happens anywhere else. Since it happens very fast, I can't get a good look at it, but the "line" is not distinct, rather, it's fuzzy or jagged. It just flashes with an accompanying click sound, and then disappears.
The monitor is a Dell P780 with a Trinitron tube.
I'm going to research this a bit more as this monitor's warranty expires in about 2 months :)
Posted 05 February 2003 - 04:26 AM
If you think that my monitor may be a fire hazard, I'll definitely will start turning it off when I leave the apartment. I don't always do that now.
It does not happen often at all. Yesterday it happened twice, but sometimes several days (weeks?) passes without problems. It looks and sounds like an electrostatic discharge, and I think you (mattsaccount) are right about it being a horizontal line somewhere in the bottom half of the screen. If you get a response from Dell, will you please post it here?
Posted 05 February 2003 - 06:25 PM
[QUOTE](Previously I asked on this forum why the monitor was generating a constant high frequency sound and was told that this propably was due to dying capacitors. However, I resolved the problem (the high pitch sound was very annoying) by simply changing the refresh frequency.)
It is probably likely still due to a dying capacitor. An Optiquest monitor that I know of emits a high-pitch squeal that I recognized as (probably) being a capacitor, as I have some background in electronics. The noise is only present (or audible) at certain resolutions and refresh rates, but which ones emit the squeel seems to change periodically. I opened the monitor and found that the sound was almost certainly coming from one of the circuit boards, and the only part on a circuit board I know of which can emit a squeel (other than a speaker, obviously) is a capacitor. I would spend the time to find the specific capacitor and replace it, but fiddling with a powered monitor is not a good idea, especially when it works fine.
Presumably the capacitors are used for timing (which is what they are often used for) and only certain ones are used for certain frequencies, but that's just my guess.
Anyway, on another monitor--an old (1992/3) "Socos" 14", that same thing occured several times. The last time this happened, the monitor started to actually smell, indicating it was completely fried, and it would not respond to video signals for hours. Several days later after it had been unplugged, I tried it again and it has worked perfectly ever since. To this day I have no idea what happened or why it works now. Anyway, prior to that several infrequent anomolies like you describe occured, sometimes when moving the VGA cable (it may have been loose). Other than that described above, this never caused any problem. The monitor works today.
[QUOTE]Should I be worried? Should I start saving for a new monitor?[/QUOTE]It wouldn't be a bad idea to have an emergency stash handy in case the monitor dies, but I wouldn't replace it until it actually bites the dust.
Posted 08 February 2003 - 03:15 AM
Yes, I would be tempted to replace the monitor.
The clicking sound may be either (a) internal arcing
Is that bad? Or could it just be "dust in the monitor" (inside the case, not the tube, obviously) causing the arcing?
Posted 08 February 2003 - 04:17 PM
I've been told it's a breakdown in the insulation on the field coil on the tube. Under certain circumstances the HT can arc across the coil, collapsing the field for a millisecond. That gives the flash and bright line (the gun is drawing on a single point for a short time).
I don't know if this is correct, seems plausable to me considering the guy that told me about it has been fixing TVs, scopes and monitors in a university for 30 years or more.
It shouldn't shorten the life of the monitor, it will remain safe. It can scare the living crap out of the person using the monitor, though
Posted 11 February 2003 - 05:41 AM
Posted 11 February 2003 - 06:14 AM
Are you sure? My monitor does not have that touch-button style power switch. It's a real old-fashioned you-have-to-push-quite-hard / clicking / two-state power switch.
BTW: pressing the power switch on the monitor doesnt turn off the monitor completely. If it is still plugged it, then it's still on - thus a fire hazard.
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