[Tig] Tig:Ursa CRT when not in use

peter swinson peter_swinson at compuserve.com
Fri Aug 10 11:39:09 BST 2007


Regarding Ursa CRTs
The best source for info is Cintel or Brimar.

Ursa was designed to put the CRT into low beam current when idle, a Brimar
recommendation. 
If I remember rightly it is not good to leave the heater on without any
beam current, cathode poisoning etc.

Ken's suggestion about leave on full beam, wide patch and slightly
defocused may help with burn, but only by burning the rest of the phosphor
to match!.

If your work does not involve zooms or changes in aspect ratio, in other
words the same size patch all the time, then there is little need to
balance the rest of the screen. In such cases I guess total switch off is
best, for overnight. However if  further sessions are due within a couple
of hours it is probably best to just go into standby, Heater on, lower beam
current. Bear in mind that the CRT has a thermal mass, and it takes
sometime to stabilise, both from a emission point of view and focus. Of
course Brimar would prefer you left the tube running at full beam all the
time. If you do, then take Ken's advise. Spread it with the zoom and
defocus slightly. 

These are only my opinions,  as I say check with Cintel or Brimar, the
reasonings may have changed since my days at Cintel.   

Cheers

Peter




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