Good morning,
I am new to the forum and I'm not sure this is the most appropriate section. I landed here reading a thread on the inspection of 3-500z tubes.
I would like some help in evaluating a Brown Boveri Q450-1 transmitting tetrode that I recently bought for a few bucks.
Unfortunately my experience with "big" transmitting tube is limited.
The first big concern is a misalignment between the cathode/grids assembly and the big graphite plate. In theory they should be perfectly coaxial but the anode seems bent. I recently acquired a big F6003/p600A pentode, NIB, which arrived damaged by the transport, completely skewed and bent (it was perfect before shipping). However, the anode rod of this Q450-1 seems very sturdy to just bend, so I was wandering whether it could be in the construction tolerances of the tube.
Second point, the tube was sold as NOS. I am quite baffled by this because the pins look scratched. On the contrary, the anode is in perfect conditions and the pins inside don't show any sign of usage, as well as no browning of the glass. At the bottom, close to the base, it is visible a small shiny part, just for 1/4 of the circumference, which resembles a getter. I know these big tubes should not present any better on the glass, being the graphite anode coating the getter material. I looked around and used transmitting tube don't usually look like this, but rather they go brown before having any shiny part.
I also guess that intensive usage would create a uniform (on the whole circumference) deposition of sputtered material, given the symmetry of the tube. The filament shows continuity.
I found some documents of Brown Boveri from the 60's but nothing really useful.
On a last note, I know the tube might be gassy, I plan to "cook" it a little bit before using it in case.
Sorry for the long list of doubts, any help would be appreciated.
Thank you,
Davide
I am new to the forum and I'm not sure this is the most appropriate section. I landed here reading a thread on the inspection of 3-500z tubes.
I would like some help in evaluating a Brown Boveri Q450-1 transmitting tetrode that I recently bought for a few bucks.
Unfortunately my experience with "big" transmitting tube is limited.
The first big concern is a misalignment between the cathode/grids assembly and the big graphite plate. In theory they should be perfectly coaxial but the anode seems bent. I recently acquired a big F6003/p600A pentode, NIB, which arrived damaged by the transport, completely skewed and bent (it was perfect before shipping). However, the anode rod of this Q450-1 seems very sturdy to just bend, so I was wandering whether it could be in the construction tolerances of the tube.
Second point, the tube was sold as NOS. I am quite baffled by this because the pins look scratched. On the contrary, the anode is in perfect conditions and the pins inside don't show any sign of usage, as well as no browning of the glass. At the bottom, close to the base, it is visible a small shiny part, just for 1/4 of the circumference, which resembles a getter. I know these big tubes should not present any better on the glass, being the graphite anode coating the getter material. I looked around and used transmitting tube don't usually look like this, but rather they go brown before having any shiny part.
I also guess that intensive usage would create a uniform (on the whole circumference) deposition of sputtered material, given the symmetry of the tube. The filament shows continuity.
I found some documents of Brown Boveri from the 60's but nothing really useful.
On a last note, I know the tube might be gassy, I plan to "cook" it a little bit before using it in case.
Sorry for the long list of doubts, any help would be appreciated.
Thank you,
Davide
...runna pile-up on 6m SSB