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Author Topic: Reconditioning 8877 tube  (Read 2288 times)
KG6YV
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Posts: 506




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« on: August 04, 2011, 11:14:42 AM »

I have an 8877 amplifier that has not had any power applied for over 10 years.  I have replaced the filter board and checked out
everything else so I am ready to apply power with the 8877 installed.  Is there any break-in/reconditioning I should do before ever trying to apply RF to the amplifier to recondition the 8877?  I know about how to do this with 3-500Z's that have been on the shelf but not the 8877.  Will running the filaments without anode voltage applied allow gettering to kill any "bad-stuff"?

Thanks for your help,

Greg
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W1QJ
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« Reply #1 on: August 04, 2011, 12:22:11 PM »

Most ceramic tubes like the 8877 unlike the glass tube will getter gas with just filament voltage.  if you apply filament voltage for about 12 hours or so without HV it should be fine.
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W8JI
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« Reply #2 on: August 04, 2011, 03:05:57 PM »

I have an 8877 amplifier that has not had any power applied for over 10 years.  I have replaced the filter board and checked out
everything else so I am ready to apply power with the 8877 installed.  Is there any break-in/reconditioning I should do before ever trying to apply RF to the amplifier to recondition the 8877?  I know about how to do this with 3-500Z's that have been on the shelf but not the 8877.  Will running the filaments without anode voltage applied allow gettering to kill any "bad-stuff"?

Thanks for your help,

Greg

Ceramic external anode tubes are easy to getter. They getter from filament voltage.

Ceramic tubes virtually never leak gas, so they virtually never need gettering.

Ironic that the tubes that are very easy to getter almost never have issues with gas ingress and do not need gettering.  :-)
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KG6YV
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« Reply #3 on: August 04, 2011, 05:02:26 PM »

Thanks for the help guys, 
One more observation,  maybe ceramic tubes never need gettering because they are so "freaking" expensive....

 
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W8JI
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« Reply #4 on: August 05, 2011, 07:12:32 AM »

Thanks for the help guys, 
One more observation,  maybe ceramic tubes never need gettering because they are so "freaking" expensive....

 

They just have much better sealing and almost always less porous internal materials.
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