[Amps] SB-220 update and gettering

[Joe]

Now I have been getting conflicting answers on initially bringing up a 
pair of these 3-500Z's from a long rest. (almost 25 years) Some say 
power them up with filament voltage only first and very slowly using a 
variac. Te others say NEVER run them at non small window spec'd voltages.

so what is it?

Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 11/27/2016 12:25 AM, John Lyles wrote:
> It is my understanding that the 3-500Z has a filament heated getter 
> that is always active when the tube is on. Also, if it has a special 
> coated anode with gettering ability, then that is active. If the anode 
> is one of the reactive metals like tantalum, then it will also getter 
> the tube. From what I am hearing, the new graphite anodes have 
> coatings that will help, but I am not familiar with those.
>
> So the answer is yes, there is always getter action on power tubes, 
> not just the flash getter that works during manufacture.
>
> John
> K5PRO
>
>
> n 11/26/16 10:29 PM, amps-request at contesting.com wrote:
>> Message: 3
>> Date: Sat, 26 Nov 2016 18:15:48 -0600
>> From: Lee <L at w0vt.us>
>> To: amps at contesting.com
>> Subject: Re: [Amps] SB-220 update and gettering
>> Message-ID: <f91c59b0-5a82-ee12-94aa-ea4842cdecf9 at w0vt.us>
>> Content-Type: text/plain; charset=windows-1252; format=flowed
>>
>> John,
>>
>> OK I understand what you are saying.  But, how does a graphite 3-500Z
>> tube get gettered after sitting around?  You say heating the anode to
>> glow does not getter the tube.  I realize the graphite tube was gettered
>> when manufactured.  Since glass seals leak, can a graphite 3-500Z be
>> gettered again down the road or was it a one time deal at the factory?
>>
>> Lee, w0vt
>
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