[Amps] Centurion plate current issue

[Alek Petkovic]

We had something similar at my club with a GU84B tube.

When the tube warmed up, there was a connection between grid and 
cathode. It still worked but got very hot. Fault was not evident when 
tube was cold. Replaced the tube and problem went away.

Whilst on that subject, does anybody have any theories or suggestions 
to clear the fault in the tube. We have a spare socket and heater 
transformer and so we have thought of a rubber hammer or discharging 
a capacitor through the fault when the tube is hot. We have 
nothing  to lose as the tube is buggered so all suggestions will be 
considered and/or tried.

73, Alek.
VK6APK


At 02:26 AM 8/06/2010, Gary Smith wrote:
>Hello to the group.
>When I switch on the centurion amp, the plate current meter is 
>resting at zero.
>Then a click is heard, the plate current meter jumps up to 300 Ma. 
>Cannot dip the plate, still have Po tho.
>Any suggestions where to look first?
>73,
>Gary...wa6fgi
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