04-05-2016, 09:18 PM
In a radio from Kirk (a GM Delco I thinkl, a typical AA5 with curtain burner dropout cord, the output tube is the 43, a pentode with 25V filament.
After some of the changes I made (the radio is a disaster with bunch of missing stuff plus discrepancies with the sch which I am not sure are factory or rework) radio briefly worked, then ceased to. There are some things I am not sure I understand, but as a result I pulled the 43 and found it has a short between the heater and Cathode.
That is my Hickok 600 shows the glow on the switch position #3.
It only occurs when the heater is on for a few secs.
I ordered another tube on eBay, says it is good and since it was no name i was sold cheap. Came today. And when I put it in my Hickok, it showed the same short in the same position. Then after pulling it out and putting back in, I saw this: instead of solid glow in the position #3 it would persist fo 1-2 seconfs and then extinguish.
Again only when filament was hot.
Eventually this also disappeared, and now it tests as all other positions, that is short flicker of the neon lamp and no glow afterward. That is it tests good. But it wasn't first!
Anything I should know about 43 pentodes?
After some of the changes I made (the radio is a disaster with bunch of missing stuff plus discrepancies with the sch which I am not sure are factory or rework) radio briefly worked, then ceased to. There are some things I am not sure I understand, but as a result I pulled the 43 and found it has a short between the heater and Cathode.
That is my Hickok 600 shows the glow on the switch position #3.
It only occurs when the heater is on for a few secs.
I ordered another tube on eBay, says it is good and since it was no name i was sold cheap. Came today. And when I put it in my Hickok, it showed the same short in the same position. Then after pulling it out and putting back in, I saw this: instead of solid glow in the position #3 it would persist fo 1-2 seconfs and then extinguish.
Again only when filament was hot.
Eventually this also disappeared, and now it tests as all other positions, that is short flicker of the neon lamp and no glow afterward. That is it tests good. But it wasn't first!
Anything I should know about 43 pentodes?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
