[Boatanchors] 539 tube tester problem

[Richard Knoppow]

    All I can think of is something temperature dependent but 
that's probably not much help. Do you have another tester to 
check these tubes? I wonder if the filament emission is going up 
with time. Seems far fetched but can be checked with another tube 
tester. Also, see if there is something in the circuit which is 
common to the tube types that have this effect and look there for 
something getting hot.

On 8/5/2020 6:38 AM, Yongsurk Lee, HL1FB wrote:
> This is HL1FB/WW6N in Seoul, Korea. I have been repairing tube equipments
> here in Korea for many years as a hobby. I successfully repaired about 200
> TV-7s, TV-2s and some Hickok tube testers.
> I had a Hickok 539A and a 539B which I could not find the exact cause of
> the problem. When I test tubes like 6L6, the test values increase as time
> goes by. Right after turn on it may indicates 6000 but after 30 minutes it
> goes up to 8000, then 9000.....
> I tried 50VAC and 10k ohm in series and applied between plate and cathode
> at different ranges. They all indicate correct values with no increase with
> time. Grid signal voltage is contant with time.
> Do you have some idea what can be problem?
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Gary Harmon, K5JWK
> ** For Assistance: gharmon at idworld.net **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to 1oldlens1 at ix.netcom.com

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL