Vertical frequency won't lock - Hantarex Polo with x600 and crt_emudrivers

[chris2922]

This weekend i finished configuring my Dell optiplex 780 to mame my Silverline jamma cab.  The Dell now has Windows XP 64 and I'm running crt-emudriver with a Radeon x600 connected to a Jpac.

I was using an LCD during initial setup and Installed the video drivers last. As expected, on reboot the LCD could no longer display the desktop and confirmed the PC was outputting 15khz.

Great! Or so I thought.

Connected to the Hantarex Polo 20" monitor via the jpac the image will not lock on the vertical axis. It keeps rolling.

I have a small potentiometer board for making positional and frequency changes but I can't get it to set the vertical frequency. It feels like I cannot make a fine enough adjustment.  Even if I could lock the 640x480i desktop resolution it wouldn't help, because the Arcade OSD 1.4 testing software shows me that different resolutions cause the vertical frequency to be more or less out of sync.  Some even cause the direction it rolls to reverse.

So I'm at a bit of a loss.  Someone has suggested a cap kit will help but I don't understand why.

I think it's the PC causing the problem because everything's fine with a Jamma Board plugged in.  With a game board plugged in I can find vertical lock with a lot of tolerance, and it's about in the middle of the pots turning circle as id expect.  With the PC connected its towards the end that it settles, and it just won't lock.  Its quite an imprecise solution and i'm not used to having to make such fine adjustments with it.  Don't think i'm being heavy handed either - i don't think its possible to find the sweet spot with the PC connected.  And even then it would unlock when the resolution changes.

Its just so strange!  I have about 10 jamma boards and changing between them has never meant i needed to change this setting. It's never needed me to touch it.

Any advice at this point would be greatly appreciated.

Could it be the X600 or the crt_emudrivers causing the issues?

[Calamity]

What happens outside Windows (during the boot process, Windows load screen)? Does the image lock on the vertical axis even with the typical JPAC's split screen?

[chris2922]

During the POST process and during windows boot up, the screen still fails to lock the vertical frequency and rolls as it does after boot.  At least that rules out the video driver, because at that point it's not been loaded.

Maybe my x600 is faulty? It's listed as compatible so that can't be it.

[Calamity]

During the POST process and during windows boot up, the screen still fails to lock the vertical frequency and rolls as it does after boot.  At least that rules out the video driver, because at that point it's not been loaded.

Maybe my x600 is faulty? It's listed as compatible so that can't be it.

Is your jpac correctly powered? (It needs to be connected to the usb to get its power from).

[chris2922]

The jpac was connected to the PC with a VGA and ps2>USB cable. I could think of nothing else to try so I replaced the cable, and it not only fixed the vertical lock problem, the screen brightness also increased noticeably.

Thanks for the replies, it's displaying a great picture with the few games I've tried.  The desktop is still a bit wobbly / flickery but presumably that's an interlaced image.

Tried mortal kombat and the video mode is a pixel off so I think I need to create some more video modes.  Now the fun part begins!  Thanks again.

[chris2922]

Rather than create a new thread I hope this is related enough to add here.

Now that my jpac is getting enough power all the lower resolutions are working great.  I also love the way GroovyMame shows me the target resolution and the resolution it has selected.  Excellent stuff.

Unfortunately my 15khz polo monitor is not displaying 640x480i very well at all.  It's not rolling on the vertical axis as before, it's just 'wobbling' a lot.  So much I can't read text which is frustrating as I have extra config work to do and with the CRTemuDriver installed I can't plug my LCD back in 

I've selected 320x240p as my desktop resolution with ArcadeOSD but can't really use windows like this.  So I'm just wondering, with everything working so nicely at lower resolutions what might be the problem with 640x480i?  Maybe my old monitor just doesn't like it?  Would a cap kit help this sort of thing?

[Calamity]

Interlaced modes look shaky by definition, but not all monitors display interlaced modes fine. I've seen old monitors where odd and even filelds are disaligned for some reason, creating a very nasty "shutter" effect. The same model of monitor but in better condition and the same modeline provides a hardly noticeable flicker. But I haven't seen a case where the flicker was so bad that you coudn't read texts.

You can perfectly plug an LCD for configuration with CRT Emudriver. Just plug it to the other output, display panel->detect screens->set the screen with its native resolution. If you're in W7, don't close the display panel, do your config and unplug the screen when you finish, then run detect screens again so the LCD goes undetected, and close the dialog. DO NOT boot the computer with the LCD attached or silly Windows will probably move to that screen.

[chris2922]

Unfortunately my little half-height X600 only has one DVI output and an s-video so I'm thinking my best bet would be a boot into Safe Mode to bypass the video driver and work in VGA.

[krick]

For a non-interlaced video mode for windows, try 640x288.  It's more usable than you'd think.

You might want to try some other interlaced resolutions to see if they're better.  I used to use one,  I think it was 512x512i or something like that.  It looked way better than 640x480i on my arcade monitor, and since it was taller, it played nicer with desktop programs that always want to have buttons of the bottom edge that's cut off so you can't get to it.

[chris2922]

Unfortunately 512 x 512 wobbles on my CRT too.  It's an old tube so maybe it just doesn't like the higher resolutions.

I'm using 640 x 240 though without problems and that looks ok.  It's improved the display in the front end too (Attract Mode) which looked blurry on the lower res.  Shame I can't run 640 x 480i.

[krick]

I'm using 640 x 240 though without problems and that looks ok.

Try 640 x 288.  On a tiny screen, 48 extra lines makes a big difference.