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Main => Monitor/Video Forum => Topic started by: mamenewb100 on March 03, 2013, 08:40:05 pm

Title: Warped screen issue
Post by: mamenewb100 on March 03, 2013, 08:40:05 pm

I have an issue with my makvision monitor where the screen warps at certain combinations of horizontal and vertical frequencies. This is not caused by being out-of-range. In order to have all the games work without a warped screen, I'm forced to raise the Khz frequency to 33. Which is way above the normal 31.4. This results in losing about 3 inches of usable screen size. I haven't heard of anyone else having this problem or even understanding what I'm talking about, so I took a couple of snapshots.

One is a fullscreen snap of a game. The other is a snap of the same game at slightly different frequency resulting in the warped image. I've had this issue since day one of getting the monitor and am hoping it's not faulty. Maybe just an adjustment I can make or a bad capacitor that could be causing this? It's very frusterating and ruins the arcade experience. :(

Title: Re: Warped screen issue
Post by: mamenewb100 on March 04, 2013, 07:22:16 pm

I'm hoping I haven't baffled the monitor gurus on this.  Just want someones best guess as to what causes this. It could be the monitor settings but it only seems to happen with certain games at certain frequencies.

Wondering if is more likely to be the tube itself (hopefully not) or just some faulty cap that I can swap out.

Title: Re: Warped screen issue
Post by: qrz on March 10, 2013, 11:08:45 pm

monitors function best when fed the scan frequency to which it is designed .

the electron beam can only be dragged across the screen at a speed determined by the LC parameters of the H/V deflection
circuitry.

multisync units will switch in/out extra capacitance ( usually in Horizontal)  to accommodate a desired timing range .

operation outside of these parameters will result in the very symptoms described...

Title: Re: Warped screen issue
Post by: mamenewb100 on March 11, 2013, 02:23:10 am

Quote from: qrz on March 10, 2013, 11:08:45 pm

operation outside of these parameters will result in the very symptoms described...

Thanks. Just wanted to know if it was normal. I know others speak of scrolling or garbled images when there is a bad frequency but didn't know about the bending.

I've had it happen to games that worked perfectly fine and then suddenly got a bend in it despite changing no settings whatsoever. Very bizzare but I'll have to work around it.

Title: Re: Warped screen issue
Post by: Calamity on March 11, 2013, 06:00:58 am

Hi mamenewb100,

Is this a consistent issue with certain games or does it just happen sometimes when loading those particular games?

What I would try is, change your desktop/frontend resolution to something that's close to most of your games. For instance, my Polostar fails recognizing some 15 kHz resolutions and doesn't switch properly, when the fronted is at 31 kHz. If I use a 15 kHz frequency in the frontend too, then this doesn't happen. Ok I have less resolution for the frontend but I care about games not frontends. Now your case is different because the Makvision is not multisync, but whatever. Try using a 120 Hz modeline for the frontend too.