Could you spot a bad vacuum tube if you saw one?

[LeapFrog]

I have this HP 430C Microwave Power Meter I recently bought online.
The manual says copyright 1955, someone has been inside of it more recently (Before Me )

Just by looking at the "glow" of the internals of a tube can you see that one has failed?
For instance two or three tubes do not "glow" like the rest, instead towards the top I see two bright red-hot spots.
I assume something is wrong.. But I don't know! The unit turns on, and kind-of gets stable...

I can link in a youtube video if anyone wants to see what i'm talking about.
Thanks for any input.

 

[BJ radionut]

http://cp.literature.agilent.com/litweb/pdf/00430-90004.pdf

Some of those tubes may not show much of a "glow"...best thing to to is test them and find out.
Link should help if you don't already have the service manual.
GL
All the Best
Gary

 

[LeapFrog]

http://cp.literature.agilent.com/litweb/pdf/00430-90004.pdf

Some of those tubes may not show much of a "glow"...best thing to to is test them and find out.
Link should help if you don't already have the service manual.
GL
All the Best
Gary

Thank You for the heads up on the glow, & as well for the link.
The unit came with a user manual & that's all.

Testing tubes will be a fun new experience for me!

Have a great day Gary
-Sam

 

[BJ radionut]

Sam: looking at the tube compliment...with the exception of the 5Y3 rectifier tube...most of those should be pretty straight forward to test with most testers. I did not notice any "strange" tubes that would not be hard to find. Hopefully the unit will just be out of calibration a little, but due to age I would be looking for "spares" just the same.
The service guide should help you identify the configuration of the meter you have, as I noticed this meter my not work well on some HF frequencies depending on the true model set-up...and then lowest seemed to be 10mHz.
GL
All the Best
Gary

 

[LeapFrog]

Sam: looking at the tube compliment...with the exception of the 5Y4 rectifier tube...most of those should be pretty straight forward to test with most testers. I did not notice any "strange" tubes that would not be hard to find. Hopefully the unit will just be out of calibration a little, but due to age I would be looking for "spares" just the same.
The service guide should help you identify the configuration of the meter you have, as I noticed this meter my not work well on some HF frequencies depending on the true model set-up...and then lowest seemed to be 10mHz.
GL
All the Best
Gary

Gary this knowledge gives me some confidence, I will have to buy/build a tester.
Yes the "Microwave" part was a good indication I may have some trouble with lower frequencies although on YouTube I have seen the same model meter used for an HF 4 Watt citizens band transceiver (shocking I must say). I'm unsure of the attenuation that was used, & I can no longer find the channel the video was on.
Also no bolometer was provided so I must locate one eventually.

Thanks Again
-Sam

 

[Captain Kilowatt]

If the tubes that look different are voltage regulator types they WILL look different. They typically start with OA as the tube type like OA1 .

 

[LeapFrog]

Thank You Captain Kilowatt, I'm on the mobile platform right now so it's difficul but when I get home I'll be able to access the PDF file and look up some part numbers.
I made a small video clip of the vacuum tubes and operation so I can cross reference parts list with the footage to see which ones are glowing" differently.


Part of me feels like I'm going backwards with this technology but I know I should start at the roots!
Maybe next year I will build a spark gap experiment (just kidding, I don't want be the cause of QRM)

-Sam