Hi. Thanks for the reply. I'm currently using the Thompson with some old   
   industrial equipment which outputs CGA. Works well. I think I have the switch   
   at position 1 but I'm not near it right now to confirm.   
      
   I recently acquired some equipment that outputs MDA and I'm trying to figure   
   out if any of the 'monochrome' modes on the 4120 will support the 18.43khz MDA   
   hsync.  I don't want to risk damaging the 4120 display.   
      
   Thanks   
      
   --- SoupGate-Win32 v1.05   
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)