Error on screen says Master /BackUP Terminal not switched on
but it is on I have Rebooted and done Flag Clear but still error
message is on the screen so not able to log in and clear
Can anyone help?

I had the same on a terminal that had been stored for a long time,
I did a full reset after replacing the cmos battery.
it cleared and screen sain "init" (initial clear) but hung,
i had to unplug the new cmos,re set again,then reconect the cmos.
lets hope yours is a simpler fix than cmos battery failure.
(as you have to reprogram it (unless you have a back up register or cv10 saved)

Try doing a SYSTEM RECONFIGURE. I think it is in manager mode

If you need a manual
http://the-checkout-tech.com/manuals/ca ... anual.html

yes trued sustem reconfig but it wont let you log in and foing fclear