[Amps] Advice

[Ron Youvan]

< There is a broadcast station that has kept a set of finals in stand bye,
running at mildly reduced filament  voltage, not dark heat,  for something like
30,000 or 40,000 hours... Had the tubes tested and they still met new specs..
Last thing I read the tubes are pushing 70,000 hours... Perhaps someone in the
group with a better memory, or better sources, can elaborate...
>

   I ran EEV/E2V K3672-BCD 65 kW klystrons past 100,000 hours, operating them 24/7 except for 5 
hours Monday morning, but I used "black heat" when beam Voltage was not present.
   (this dropped the filament Voltage from 8/8.5 Volts to 6.0 Volts) This 240,000 Watt transmitter 
operated at only 200,000 Watts, 55 kW from each tube instead of 65 kW)
Someplace past 105/6,000 hours the tubes "fall apart," so we replaced them just after 100,000 hours.
  --
    Ron  KA4INM - The only real problem is death is so final.