TFT Monitor problem solved. FYI

[basa]

Probably of no great interest but perhaps may prevent some people head scratching over a monitor fault.

I have been using a Compaq TFT Monitor quite happily for about 9 months now (originally bought off eBay) on the end of my nVidia MX420 and W98SE system. About a month ago I upped the screen resolution from 800x600 to 1024x768 with no ill effects.

I came home wednesday evening to find the display extremely blurred and fuzzy. The effect was almost as if it were being affected by electrical interference. I switched the monitor off and on, rebooted the PC, re-installed the nVidia software and reseated the card (not all at the same time) all to no effect.

Reducing the resolution back to 800x600 cured the problem, but every time I reset the resolution to 1024x768 the problem returned and definitely seemed to be being affected by HDD activity (when the HD was busy the distortion was worse, when the HD was quiet, the distortion was reduced although still bad).

With fingers crossed I nipped out and bought a new SVGA cable and cheapo graphics card (MX4000).

As soon as I replaced the video cable the problem disappeared !!!

Anyone had this before ? How can a cable 'go faulty' just like that, but not enough to disable the monitor entirely ? I suppose an earth lead protecting the cable from RF or other stray interferences must have become detatched or making poor contact or something.

[altis]

Did you not try 'aligning' the monitor first? Not a problem for DVI monitors but analogue ones need to be aligned with the signal or they look fuzzy.

[basa]

Originally Posted by altis

Did you not try 'aligning' the monitor first? Not a problem for DVI monitors but analogue ones need to be aligned with the signal or they look fuzzy.

No, the images weren't fuzzy as in soft with no sharpness, they were shaky, vibrating not a static state, a bit like a TV picture being affected by electrical motor interference, spiky. I'd swear it was electrical interference from some component within the PC case close to the vid card or vid cable, as I said it did vary with HD activity. What I cannot fathom is why it disappeared a lower resolutions ??

[kfridge]

what is the refresh rate of the card set to..? TFT's usually only need to be set to 60Hz, above that they can show problems

[j52c]

had a similar problem to this but not with a monitor.

I bought a Toshiba wide screen tv package with dvd player, video recorder.

When recoding from bbc1 and playing back the tape, there was a couple of thin lines across the tv screen.

I rang the shop I bought the system from and they came and replaced the video recorder saying it the video heads were out of line.

Anyway, after doing a recording, the problem was still there. I thought, can't be 2 videos the same, so, sat down a minute and thought.

After a few more minutes, I went upstairs to get a spare RF lead, swapped them over and there it was, recording and playback fine.

So it could be the cable.

[basa]

Originally Posted by kfridge

what is the refresh rate of the card set to..? TFT's usually only need to be set to 60Hz, above that they can show problems

The info from Compaq indicates a refresh rate of 70Hz @ 1024v768 and 85Hz @ 800x600. I assume this is the rate in use (70Hz @ 1024x768), but I must check I have the correct .inf file in place for the monitor.

---------- Post added at 12:40 ---------- Previous post was at 12:39 ----------

Originally Posted by j52c

................So it could be the cable.

It WAS the cable (see my OP). All is working fine now.