[radiotvnut]

When I was about 13 or 14, back around 1990, a TV shop gave me an old blue B&K 465 CRT tester/rejuvenator. Even in 1990, it was highly obsolete and he probably hadn't used it in years. Still, I was happy to get it and it would check older delta-gun color tubes and B&W tubes, which was the majority of what I was getting, at that time. It had three rejuvenate settings and I found out quickly that you'd better be careful, or the tube would be worse than before. I had pretty good luck with rejuvenating the older large-neck B&W tubes. The small-neck tubes, like what was in the 9" and 12" sets, was a hit or a miss. Sometimes, rejuvenation would work and hold up, sometimes it would come up and fall back down, and there were a few times when the tube would get totally wiped out. As far as color tubes, I never had any luck getting a color tube to stay up with that tester.

By the mid '90s, I was seeing more and more sets with inline-gun tubes and the old tester could not handle those with the sockets I had. I later found out that there was an "SP65" socket adapter that would allow the newer sockets to be used with the old tester, but given the crude rejuvenate function of the old tester, I probably needed a better one.

So, I broke down and bought a new B&K 480, about $875 at the time, and it would test virtually any tube that I ran across.

I used the B&K for years and in the very last days of CRT TVs, I found a Sencore CR70 at the flea market for $25. That tester was built better and seemed to be more advanced than the B&K, but the B&K was easier to set up. I used the Sencore for a while, until it developed a problem that I've never fixed.

Currently, I still have my old B&K 480, a couple of 470s, one or two 467s (the one with 3 meters), a 466, and a 465 (all in various states of disrepair at the moment). I have the Sencore CR70 that has issues, and I have a mid '70s RCA tester.

Even with later model testers, there were still some tubes that I just didn't have very good luck with. These tubes include:

1. '90s Zenith color tubes, especially the 25" and 27" tubes. Those tubes were garbage to begin with and it's hard to get anything good out of something that was garbage to start with. Those tubes would prematurely get weak and/or intermittently short/arc. When they shorted, they blew up other parts (usually, the power supply and/or video driver circuitry).

2. Late '70s-early '80s Zenith inline tri-focus tubes, especially the 23" and 25" tubes. When they were strong, they looked great, but when they got weak, there was not much you could do. At best, rejuvenating them might help a little, but they never bounced back fully and they'd never stay up long. The 13", 17", and 19" versions seemed to last longer.

3. Sony Trinitron tubes. If rejuvenating them didn't blow up the tube, they'd often look good for a short period. Then, they'd fall back down and look worse than they did before you rejuvenated them.

4. The 12", and smaller, B&W tubes with the small neck. I've had luck with a few of those, but I've had more of them that either wouldn't come up at all or they'd fall back down in short order.

5. In the late '70s-early '80s, RCA had some crap delta-gun tubes that would short and/or lose emission, and they wouldn't take a hit very well. The older RCA jugs would take a hit and keep right on going.

6. The 25V Sylvania black-face delta-gun tubes. They produced a great picture but didn't last long and usually would not take a hit.

It should be noted that rejuvenation should not be considered a permanent fix. Some tubes will hold up longer than others, but rejuvenation was mainly meant to buy the customer some time, while a replacement tube could be sourced, or the customer prepared to buy a new TV. In today's world, it's not as simply as ordering a new tube and rejuvenation is often all that can be done to save an old TV.