Agreed, either it will or will not function. Open filament or shorts to the
case tend to be common failures, cracked or broken magnets due to
overheating or mechanical stress. Continuity check across the filaments for
low reading and from filament leads to case for open.
"Sam Goldwasser" wrote in message
...
(Ken G.) writes:

Its hard to tell on these new invertor ovens ..The tube can test totaly
normal on an ohm meter but not work in the oven .

Invertor power supply or not, this is true. Test the filament, test for
shorts, closely examine for physical problems like cracked magnets.
Beyond that, ruling out other causes and then going for a replacement
is about the only safe option.

--- sam | Sci.Electronics.Repair FAQ Mirror:
http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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