[Amps] Alpha 87A - Gettering NOS 3CX800A7's

[TexasRF at aol.com]

Hi All, I have found that using an old analog HV type VOM, such as Tripplet 
 630, as a current limiting resistor works very well. These meters 
typically have  a series resistance of about 100 megohms and limit the current to 
less than 30  microamps at 3 KV plate voltage.
 
Additionally, you can monitor the process by watching the current  
indication. Hopefully it will decrease with time. 
 
The actual voltage impressed on the tube is the plate voltage minus the VOM 
 reading. So, if the leakage causes the meter to read 2000v, the actual 
voltage  across the tube is only 1000v and the current is 20 microamperes (in 
this  case).
 
 
73,
Gerald K5GW
 
 
 
 
In a message dated 3/30/2013 7:46:34 A.M. Pacific Standard Time,  
crc at cyberlink.bc.ca writes:

Just  don't connect the plate caps while doing this gettering.    Fern

----- Original Message ----- 
From: "Rick Stealey"  <rstealey at hotmail.com>
To: "john starr001"  <jstarr001 at hotmail.com>; <amps at contesting.com>
Sent: Saturday,  March 30, 2013 8:33 AM
Subject: Re: [Amps] Alpha 87A - Gettering NOS  3CX800A7's


> If they need gettering, putting full HV on them  will cause them to arc, 
by definition.
> Maybe you could put a large  value resistor in the HV lead temporarily 
and see if they can take it.
>  
> Rick  K2XT
> 
> 
> 
>     
> _______________________________________________
>  
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