Actually, it sounds as though you need to set the eeprom
correctly for monitor type.  It's *so* long since I worked with
one of these old-mode monitors.  You can do it from the monitor
with a cryptic command like 'q88=2' or somesuch.  This is probably
in a Sun HW FAQ on the net or the front of a Sun FE guide.

HTH

Paul

P.S. *don't* try q88=2 - it's a guide to syntax only