B&k 445
 

I got this at the radio club along with that RCA TV for $5. It did something weird with my 17CP4, though. It tested fine at first, then it dropped down to 20%. I think this thing is actually putting out more than 6.3 volts, though. I'll measure it with a voltmeter and see what's going on.

Be careful with that thing if you rejuvenate a tube. I used to have one of those, and believe me, it packed a mean punch if I cranked it up to high!

I will only be using my B&K 470 to rejuvenate tubes. This tester is only for testing.

The voltage will read high without a load. The 17CP4 has a 600ma heater. That CRT checker is in like-new condition.

Don't get me wrong, the 445 is a great machine, it's just very potent. I have ruined several with one of those, but on the other hand, the 445 resurrected quite a few that nothing else would work on. I'll put it this way, if that machine won't bring a CRT back to life, nothing will.

So in summation it is a "kill or cure" proposition.

So this tester is considered the "big guns" huh? If I ever come across a tube that not even my 470 can bring back, I'll be happy to give it an ass kicking with this tester. But until then it will just be for display. I'd also like to find a B&K 465. Those are pretty cool. I just love test equipment.

The tester doesn't read voltage on the scale. It just has that switch that you select your favorite voltage on. It looked like it was putting out more than 6.3 because my 21AUP4A was lit up like a light bulb.

Yes, the 445 was the one we drug out as a last resort for tubes that were not really watchable and the customer wouldn't spring for a replacement. It was old, worn, and beat up...but it still kept on ticking. We had fabricated several adapters for use on newer bases.

We mostly used a B&K 467 for day-to-day testing and rejuvenating, and the 445 stayed on the shelf just for stubborn cases.

I just checked, and unfortunately, I don't have the right socket for my B&K 470 to test the 17CP4. Not that I really need to, but it would be nice to get an accurate reading from a reliable tester.

Even though, the tester is in like-new condition, the voltage control knob might have slipped on the shaft and someone might've just tightened the set screw. :scratch2:
This time, you'll have to check the voltages, using the B/W socket, pins 1&12. They should be just slightly higher, with no load.
BTW, the heater might be damaged in the 21AUP4, by someone that was careless with a rejuvenator. I ran into that a lot, years ago. :sigh:

Yes, for sure measure the heater voltage output of the tester with a decent voltmeter, known to be in reasonable calibration. Measure the socket with no load and also when connected to the crt. Indeed, the tester switch could be mis-registered or even mis-wired.
I would NEVER connect an un-verified tester to a nearly unobtainable CRT or even a small inexpensive vacuum tube... NEVER!

jr

Yeah, for sure! This could have been bad, but thankfully, the tube survived with flying colors. (Get it..) I'll definitely be measuring this thing before it sees another one of my tubes. Maybe Friday I can do that. I've just been so busy with band practice and my new job fixing Rainbow vacuums, by the time I finish, I have no energy whatsoever. Here is a picture of what the B&K 445 indicated the second time I tested this tube at 6.3 volts (supposedly) About 40 seconds after this photo was taken, it dropped to about 200 on the scale.

rejuv of a crt gets the filaments very hot, testing right after is just like testing a crt with a big brightner on it. To really see if there was any difference, you need to turn it of for at least 10-15 min to get cold and then try again at the correct filament voltage.

Good news! I figured out why the 17CP4 was measuring so weird on the B&K 445 - the G2 switch was dirty and making bad contact. The tube is very healthy, and so is the tester. I measured the voltage out of the tester, and it was spot on.