[NJARC] FW: tube qusetion

[Vourtsis, Philip (Phil), ALABS]

Can anyone help Lou with his tube emission question?
 
Phil Vourtsis 
Pres.- New Jersey Antique Radio Club 

EE Humor 
Resistance may be futile but capacitance has potential 

-----Original Message-----
From: Lou Pannone [mailto:lpannone at tgs-solutions.com]
Sent: Thursday, September 16, 2004 9:04 AM
To: Vourtsis, Philip (Phil), ALABS
Subject: tube qusetion



Hi Phil.
 
I tested the 7 new (not NOS) 6146B Chinese tubes on my friends Hickock (600A?). It is a good mutual conductance tube tester. These are RF output tubes for Ham radio transmitters.
 
All of the tubes read above the min spec (mutual cond value), but 2 out of the 7 read good (on the high side), but if I continue to hold the TEST button down for several seconds (which keeps the tube under load), the meter drops gradually, in some cases, by about 20% of the initial value. The final value is still above spec. Any idea if this is a problem? It's been a long time since I have used a tube tester on a regular basis. Not sure if I ever saw this even back in the 60s.
 
Thanks for any input.
 
Lou