HP Model 712/100 - Workstation Handbook page 58

Press <y> to save this monitor type.
If you don't select the monitor type that's displayed, the system will cycle through
the other monitor types, some of which the monitor won't display. Wait for the
workstation to display the correct monitor type again, then select it.
NOTICES: Some multisync monitors will "lock up" if you do
not select the monitor type on the first cycle. In this
case, power cycle the monitor to resume the selection
process.
Unsupported monitors may "lock up" if they can not
sync to a scan rate.
3–18 Configuration