RadioBanter - View Single Post

June 24th 06, 01:40 AM posted to rec.audio.tubes,rec.radio.amateur.homebrew

Gudmundur wrote:

In article ,
says...

Gudmundur wrote:

Hey my man, what you may have is a classic case of the grid coupling
capacitor breaking down and killing your bias on the grid. It is
not uncommon for the grid to go positive and cause the tube to melt!!

You haven't read the thread fully have you ?

Graham

Well let's see, the original poster said the voltage across the grid
resistor seemed wrong, (leaky cap is possible there) and he said the
current kept going up and up (leaky cap getting worse with ambient
heat from the tube) and a blue glow which I find to be typical with
many tubes of the 807 style when there is excess plate current such
as may be caused by A LEAKY CAP between the control grid of the 807
and the previous stage plate voltage.

Fine but he already said he'd checked it and it's not that.

No matter.

Graham