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electricdave80
18-09-2008, 09:08 PM
I have a flicker on our CRT Monitor which I cannot find what is causing this annoying condition, I have tried changing the setting on the monitor without success, also I have tried another monitor which just comes up completly blank, I suspect that in this case the computer is not detecting new hardware? which is another problem, please can someone help

wainuitech
18-09-2008, 09:12 PM
Welcome to PF1 -

Does the PC you have the monitor(s) connected to have on-board Graphics or a dedicated graphic card & how old is the PC ?

electricdave80
18-09-2008, 09:25 PM
The PC is about 5years old I,m not sure what sort of graphic card it has,if it even has one,? this computer is our bowling club computer and I use it for our accounting system which it doeswell using exel, but I no very little about the hardware thanks for your reply,

Billy T
18-09-2008, 10:10 PM
Is the monitor close to anything electrical like the meter box, or does it have any plug packs hiding beside or behind it? It could be electromagnetic interference.

Another test is to up the refresh rate to 75+ Hz and if the flicker goes away or diminishes then EMFs are the cause. If you can't speed it up, slow it down to 56Hz and it should flicker worse.

Cheers

Billy 8-{)

feersumendjinn
18-09-2008, 11:43 PM
Another test is to up the refresh rate to 75+ Hz


Right-click your mouse on the desktop (not on the icons or taskbar), on the resulting window, left-click Settings. In that window left-click Advanced, this will take you to the video resolution and refresh settings, left-click Adapter tab then the List All Modes button, in that list select the setting you want (800x600, 75Hz for a 14 or 15 inch CRT; 1024x768, 75Hz for a 17 inch (usually)), depends on your computers integral or separate video card's capabilities, how high the numbers go here.
Left-click Apply then Ok out of those two windows, the screen will then change to the new settings and ask you if you want to keep these settings, click Yes, you're done.

prefect
19-09-2008, 07:49 AM
Can you enter the screens menu and give it a jolly good degaussing

pcuser42
19-09-2008, 07:51 AM
IIRC degaussing only fixes magnetic interference. It won't fix flickering.

lakewoodlady
19-09-2008, 09:47 AM
You could try tapping it on the side of it and if that stops the flickering, it probably means there are some dry joints in the wiring inside it. It happened to mine like that and i took it to a repair shop. Cost me $50 to fix, which was a lot cheaper than a new monitor.

pctek
19-09-2008, 10:40 AM
I I have tried changing the setting on the monitor without successp

What setting? Flicker is usually too low a refresh rate.

feersumendjinn
19-09-2008, 05:20 PM
I have tried changing the setting on the monitor without success,
Yeah, I assumed he meant the OSD (on-screen display), which of course would have no effect.

Billy T
19-09-2008, 06:28 PM
IIRC degaussing only fixes magnetic interference. It won't fix flickering.

YRP-C Degaussing eliminates magnetisation caused by the earth's magnetic fields (and sometimes adjacent weakly-magnetised ferrous metals). CRT monitors are happiest when aligned North-South and setting up East-West usually requires a little more degaussing than usual to get the colour purity right. CRTs also come in northern hemisphere or southern hemisphere versions so that the picture sits in the centre of the screen. Stand a monitor on its head and the image will move sideways.

Just a few more little-known useless facts to help you while away the time as you patiently wait for the delayed telecast of the Warriors game, but you are right, it won't fix flickering. :D

Cheers

Billy 8-{)

PENTIUM
19-09-2008, 10:13 PM
A failing or inadequate P C power supply will sometimes display CRT monitor flicker irrespective of refresh settings.

Burnzee
19-09-2008, 10:43 PM
Hi

One of the most common causes of CRT flicker is High Voltage Arc Over. This mostly happens when dust, dirt and other crap gets attracted to the rear of the CRT tube around the High Voltage Inlet. This is a rubber sucker thing. You can clean it off with WD-40 but be very aware high voltages abound even if the monitor is unplugged and off. This high voltage can and will kill you. If you don't know what you are doing leave it to a professional serviceman. The next life you save may be your own!!

Do not allow high voltage arc over to continue. This condition puts extra strain on other components and they will soon fail.

BURNZEE

Billy T
20-09-2008, 05:44 PM
One of the most common causes of CRT flicker is High Voltage Arc Over.
BURNZEE

That's news to me! You'd get more than flicker if you had an EHT arc-over. There would be an almighty bang because the CRT represents a large storage capacitance and the arc current is very high. The discharge current often kills the electronics as well, you don't get many second chances when EHT flashes over.

Alternatively, if there is a high resistance path (surface gunk) between the EHT Rose and ground, there will usually be a pronounced sizzling noise and in the rare instances when the image is disturbed by this, rather than a flicker you get a line by line displacement or "jagged" image.

In all my (considerable) years in electronics and in dealing with HV equipment, I have never seen EHT leakage cause screen flicker, and in modern equipment such leakage is extremely rare to the point of virtual extinction unless operating in a very humid and polluted atmosphere such as kitchens, chain smokers, kerosene heaters, industrial plants, living in a swamp etc.

The cause is most likely to be one of the other options mentioned, from equipment failure through to electromagnetic interference.

Cheers

Billy 8-{)