K4600 Sync Problems *SOLVED*

[deega]

I'm having a problem getting a k4600 to sync V or H @ 15KHz.  I'm using windows xp sp 3 with Soft-15KHz and can get a picture at, say, 320x240 but it will not hold sync.  It constantly rolls both H and V slow enough to clearly see the image.  While doing this, the left and right edges are warped.  The odd thing is if I send it the signal intended for my LCD (1366x768) it syncs to THAT ("straight" edges and everything).  Of course, when it does this little trick, it displays in 3 bands across the monitor.  It DOES sync at the higher frequency, though.  The same behavior is displayed using an ATI HD4650 and the onboard Intel 945 graphics.

I have replaced all electrolytic caps, R360, TR201, TR202, TR203, TR210, and TR308 per Fromm's flowchart, but I've gotten nowhere.  

Anyone have any suggestions??  Thanks.

Oops!  I should probably add some more info.  Input path is straight from VGA to P317 input board pins 1-5.  I have verified I have Vsync attached to pin 4 and Hsync to pin 5.

[ac3]

Is the monitor hz set to 60hz? sounds like you might have it set to 75hz or higher. Which would explain why it syncs at higher resolutions as these will force 60hz.

[deega]

Thanks!

Does the K4600 have such a setting?  If so, would you be able to point me in the direction of that lever? 

Regarding the signal fed to the monitor, it's coming from a default install of Soft-15KHz with only the 15KHz modelines installed.  I have not added any custom modelines, as it seems at least a couple of the default ones would yield a sync. 

[ac3]

It's a windows setting, soft15khz sets the res but not the monitor hz. I don't know what version of windows you're using but it's usually in advanced video settings -> monitor -> refresh rate.

[deega]

Indeed.  It's set at 60Hz.

[deega]

Okay, here's some pics of what it's doing.  The blurred images on the first two are due to the constant movement on the screen, this is not how it REALLY looks.  The third is the monitor syncing to the signal intended for my LCD.

[deega]

Elementary sync problem, actually.  I'm not real sure why, but I was convinced my card used positive sync..  Perhaps it was sumbling upon the 1366x768 sync that threw me off.

Arcade resolutions on this card use negative sync.  

I've still got some issues with geometry.  I suppose this could be due to the TV tube I'm using.  It had yoke resistances matching a K4600, which is why I picked up this chassis.  I have an original K4600 yoke, which I picked up in case of this.  I'd rather not swap the yoke, but will if I must.  I'd rather swap components on the chassis to correct geometry.  Maybe this will be another elementary topic posting and educational experience in my near future.