How to identify a failing Cathode Ray Tube?

[JimB]

so I figure the 00.8 cap is bad.

Yes, I think that we would all agree with that.
JimB

 

[throbscottle]

43.8 and 93.5 are pretty good accuracy, when you consider electrolytic caps (or older types at least) can be -20% to +50% of the specified value right out of the factory.
But yep, looks like you've found one culprit. Interested to know if that was the only problem.

 

[throbscottle]

Seems crazy to only check ESR. If the cap is short circuit it will by definition have low ESR, but be completely useless. There are other parameters you can measure (apart from the value) but that's all getting a bit specialist...

 

[Tom Vaughan-Mountford]

Feeling like I've earned some proper man-points today! Thanks for the help everyone, I've learned a hell of a lot!

The problems were indeed all located within the power supply - almost all the caps were a long way from spec, there were some dry-joints, and I found a resistor with a crack in it. I replaced all the failed parts, re-soldered joints, cleaned and reassembled, then fired it up and it's needed no further adjustment

Playback is from the RGB output of a Sony Digital Betacam deck (16:9)

Thanks again all!

 

[JimB]

Excellent!
A success story is always good to hear.

JimB

 

[spec]

Well done- nice pictures.

spec

 

[cowboybob]

Outstanding, TVM. I am majorly impressed!

... Playback is from the RGB output of a Sony Digital Betacam deck (16:9)...

You do have some very interesting gear. A man after my own heart. All of my ham gear are tube types from the 50s and the 60s - limited in their way but rock solid and I can heat my house with them... .

 

[Tom Vaughan-Mountford]

I got the Digital Betacam deck at an auction, it used to belong to ITV, I picked up for just £60 - original price was circa £30,000

 

[throbscottle]

Well done!

 

[spec]

I got the Digital Betacam deck at an auction, it used to belong to ITV, I picked up for just £60 - original price was circa £30,000

The company that I worked for designed and marketed a radar recorder based on the Sony Betacam. The Betacam was a fantastic piece of kit for the time and, as you say, cost the earth.

spec