[ARC Tech-109]

I have both the B&K 466 band 467 and found the clean/balance and rejuvenate-1 functions to be much easier on the cathodes than the hard rejuvenate function which I believe just strips the cathode face away. I also reduced the size of the capacitors that are thrown across during the clean/balance on my 467 and a "lighter" light bulb ballast on the 466. As JohnCT pointed out the 467 cuts off the heater during the rejuvenate cycle and this causes them to arc heavily during the last of the heat basically destroying the face IMO, as a retired radio tech the rule was to make sure cathodes were fully heated before applying scree/plate and drawing current to avoid damage and this feature of the 467 seems to do just the opposite. Mine are modified to keep the heat on.

Tubes we can add to the list that should never be hit with a rejuvenator are the little 4" and 5" Trinitron tubes used in the BVM-5300 or KV4000 & KV5000 series sets and 90's vintage HP test equipment that use the individual fast heaters as prime emitters, the heaters themselves only pull some 40 MA each and a zap from a rejuvenator will open them... speaking from first hand experience. These tubes do have a problem with K/G1 shorting on the red from the whiskers and my solution is to run the heater at rated voltage and drop no larger than a 0.47uf cap charged to 150V across them cathode negative to pop the whisker open.

Just for the record I've had rejuvenated delta guns last a decade or more after a "dusting" with the clean/balance function and many CRT based computer monitors run 24/7 until something on the board died after a visit from my 466. I've also had Japanese delta guns die withing just a few months of a clean/balance so really it's a gamble either way. I hit the gun of my Motorola R2670 green screen with the rejuvenate-1 of my 466 almost 20 years ago and it's still going strong averaging 8-10hrs of use daily.

As the old disclaimer goes... your mileage may vary.

Retired Radio Tech-109