you will want ot tweak your /etc/X11/XF83Config file.

find and change the VertRefersh settting to 70 (or whatever you want).
VertRefersh 70

then you will want to find the screen section of your default monitor. and 
modify the proper display section.  for example (assuming a 16bit color 
depth)

Section "Screen"
  Identifier "My Screen"
  Device "Device_Configured_above"
  Monitor "Monitor_configured_above"
  DefaultDepth 16

  SubSection "Display"
    Depth 16
    Modes "720x400"
    ViewPort 0 0 #this settign should already be in 
  EndSubSection
EndSection

you may also want to check out XFree86.org for more documentation on X.

--joe

On Tuesday 30 July 2002 10:00, Peter Kozberski wrote:
> The monitor I'm looking at displays a res of 720x400/70Hz. I rang the
> supplier and asked if the OSD control was broken. No it's not, that's its
> default. How can I adjust the software settings in 1.5.2 to accomodate this
> monitor?
>
> -- Peter Kozberski