VGA sync problem with LCD

Mikko Rauhala mjrauhal at
Wed Jun 21 14:50:30 PDT 2006

'lo. Hope this is the right list for queries like this.

I've two Samsung Syncmaster 244Ts here running at 1920x1200, the other
fed via DVI, the other via VGA. I'm having trouble syncing to the VGA
input properly.

The default 1920x1200 that comes up is synced to, but it seems that the
monitor detects it as a 1600x1200 mode and, I presume, samples the
signal at 1600 places on the horizontal line, the upscales, which is
obviously suboptimal. Also, it's at the limits of the monitor's width
tuning. I tweaked the standard mode a bit to push it towards the tunable
area, which succeeded.

I experimented with to create a 60 Hz (suggested) and 56
Hz (minimum for the monitor) mode. The 60 Hz mode is still recognized as
1600x1200, and positioning is way off. The 56 Hz mode _is_ recognized as
1920x1200, but is way too narrow and positioned to the right; the
monitor tuning cannot compensate.

Modelines in the order standard, tweaked, 56 Hz, 60 Hz:
Modeline "1920x1200VGA" 230.00  1920 1936 2096 2528  1200 1201 1204 1250
Modeline "1920x1200VGA" 230.00  1920 1936 2096 2572  1200 1201 1204 1250
Modeline "1920x1200VGA" 191.49 1920 1952 2672 2704 1200 1225 1236 1261
Modeline "1920x1200VGA" 210.68 1920 1952 2752 2784 1200 1224 1236 1261

I did experiment with several of other modes to no avail. Now, if anyone
knows what might help or knows of a suitable modeline tweaking resource,
I'd be happy of any assistance. I'm especially looking for information
concerning how to properly tweak that third modeline (the 56 Hz one
which _is_ recognized as being 1920 pixels wide) so that the image would
be moved considerably to the left and widened at the receiving end.


Mikko Rauhala   - mjr at     - <URL:>
Transhumanist   - WTA member     - <URL:>
Singularitarian - SIAI supporter - <URL:>

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