Quote:
Originally Posted by radiotvnut
It should be noted that rejuvenation should not be considered a permanent fix.
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Indeed, it is a last resort procedure. Some guys will buy one and use the "clean"function as if was sort of helpful maintenance like an oil change.
With regards to CRT testers, I have four B&K 467s, and one of them I modified many years ago after reading Sencore's sales pitch outlining what was wrong with B&Ks testers in the way they cut off the heater voltage during rejuvenation. I know it was ad-copy but it made sense from what I observed using the B&K.
One thing I noticed about using the B&K is that it was often tough on the tube. When using the clean or restore, it would apply the current to the cathode while simultaneously removing the heater voltage. The meter would show the current though the cathode while the button was held down, but if the tube held the current for too long and the heater went cold, there would be a violent jerking and swing of the meter accompanied by visible arcing in the gun assy. This often happened so fast you couldn't release the button fast enough.
What I did was take my 467 apart and jump out the switch so the heater voltage stayed on during the rejuvenation. When I pushed the rejuv button, I would keep my other hand on the heater adjust button and slowly lower the heater while I watched the meter. Ideally, you want the meter to slowly reduce, but when I noticed the meter start to twitch, I'd raise the heater voltage back up until the meter stabilized. I'd then start dropping the heater voltage again until the meter moved smoothly to about 1/4 range then I'd let off the rejuv button.
That procedure seemed to be a lot easier on the cathode and I had a lot more success that way. I never used the Sencore but I think they had the right idea.
John