I rejuvenated a tube for the first time today

[fsjonsey]

The 17avp4 in my Bugeye has gotten progressively darker since i began using it in June. Today i decided to test it on my b&k 465. The results weren't pretty. Even after letting it cook on 8V filament for four hours, emission barely read 200 on a scale of 1000. I decided to go for it and use the Dynamic Intensifier. I tried the lowest setting first, but it had no effect. The medium setting took the tube just into the green. Finally, I decided to go for it and try the high setting. It worked. Emission now reads a solid 600 and stays there. As testers go, How is the 465? It seems to do the job for me.

[ohohyodafarted]

I've got one too. It's a mixed bag. I have fried the filiment on 2 crt's using the high dynamic intensify setting.

I have found that by using the "remove short" setting, you can also rejuvenate a crt with less risk of burning the filiment out.

What I do is run the tube at about 7 volts on emmission setting and then switch to "remove shorts" then I press the rejuvenate button, and go back to measure the emmission at 6.3 volts. Repeat the procedure as needed. I have repeated this as many a 6 or more times taking a tube from the 200 area to over 700 depending how much life is left on the cathode.

I also have recently purchased a Beltron restorrer. I have used it on a couple of crt's thus far. The Beltron method seems to be a safer route, but in the end a dead crt is a dead crt and when there is no life left on the cathode, it's history. I tried the Beltron on a couple crt's that I was not able to restore with the B&K, and the Beltron couldn't bring them back either.

The Beltron manual says that if a crt has never had a brightener attached, that the chances of restoring emmission are better. I guess a brightener frys what is left of the cathode.

[fsjonsey]

Thanks for the tip on using the remove shorts function. This set had no brightener when I found it. Now to find a new CRT.

[Eric H]

Did you not get my P.M.?
There's one on eBay:

http://cgi.ebay.com/1956-Zenith-Buge...QQcmdZViewItem

[fsjonsey]

Originally Posted by Eric H

Did you not get my P.M.?
There's one on eBay:

http://cgi.ebay.com/1956-Zenith-Buge...QQcmdZViewItem

I haven't checked my email lately. The price seems right, and the cabinet is in better shape than mine. Thanks for the link. Didn't that set belong to an AK'er?

[fujifrontier]

How does a rejuvenator work?

[jpdylon]

THe rejuve function puts a couple thousand volts between grids and cathode. The arcing strips away the contaminants that build up over time

--however it also strips away the nickel plating on the cathode, so it should be a last resort only. On occasion, rejuvenation can destroy the cathode rendering the tube useless.

The reason why I bought my beltron tester is that its rejuvenation method does not use high voltage discharge but rather a combination of lower voltage at a higher current with a gradual increase in heater voltage during the process. This way the cathode risk doesn't get damaged, much greater results are achieved, and the tube lasts considerably longer than with standard rejuvenation methods.

If you can get a hold of a beltron, do so. They are great machines and are almost a must if you have lots of rare CRTs.

[Tube TV]

I have ejoyed this thead , I was also wondering how they worked . I see them quite often on ebay and I have been thinking of getting one , probably a B&K . already have a TV analyst and a dynascan video generator on the way . So the end result , how much brighter is the CRT after using the rejuvinator ?

[jpdylon]

The brightness is near what it used to be before the emission dropped off. However the detail at higher contrasts will not be a sharp as they used to be. Sometimes you will see a fuzz around the edge of white text on a black background.

again, rejuvenation its a last result. however I do not hesitate to use my beltron on a weak tube. 90& of the time it comes back to life with excellent results. I retired my RCA, sencore, and B&K after using it on a few tubes that the other testers just didn't work well with.

However, if you've already used a HV discharge rejuvenator, don't expect good results with a beltron. It works with the cathode, which is entirely dependent on how much of the usable nickel plating is left. If you've already beat it up with a rejuvenator, chances are the beltron won't be able to do much.

Another important note on rejuvenation:

avoid using the highest setting, and only use the dynamic intensifier on the B&Ks for short bursts. press it for not more than 3 seconds, pausing 10 seconds between. The reason is because the HV and current that flows through the grids and cathode will make them extremely hot very fast. If you overheat the cathode or grids, the tube will die. Watch the elements closely and dim the room if possible. As soon as you see anything in the CRT other than the heater start to glow red or orange, GET OFF THE BUTTON!

[Tube TV]

Thank for the advise . Would it be a good Idea to get a Beltron , rather than a B&K as my first crt checker rejuvinator ? Im still at the shopping around stage .

[fsjonsey]

Originally Posted by jpdylon

The brightness is near what it used to be before the emission dropped off. However the detail at higher contrasts will not be a sharp as they used to be. Sometimes you will see a fuzz around the edge of white text on a black background.

again, rejuvenation its a last result. however I do not hesitate to use my beltron on a weak tube. 90& of the time it comes back to life with excellent results. I retired my RCA, sencore, and B&K after using it on a few tubes that the other testers just didn't work well with.

However, if you've already used a HV discharge rejuvenator, don't expect good results with a beltron. It works with the cathode, which is entirely dependent on how much of the usable nickel plating is left. If you've already beat it up with a rejuvenator, chances are the beltron won't be able to do much.

Another important note on rejuvenation:

avoid using the highest setting, and only use the dynamic intensifier on the B&Ks for short bursts. press it for not more than 3 seconds, pausing 10 seconds between. The reason is because the HV and current that flows through the grids and cathode will make them extremely hot very fast. If you overheat the cathode or grids, the tube will die. Watch the elements closely and dim the room if possible. As soon as you see anything in the CRT other than the heater start to glow red or orange, GET OFF THE BUTTON!

Yeah, i only tapped the button for less than a second when i did mine.

[jpdylon]

Originally Posted by Tube TV

Thank for the advise . Would it be a good Idea to get a Beltron , rather than a B&K as my first crt checker rejuvinator ? Im still at the shopping around stage .

The beltrons show up now and then on ebay, but be prepared to pay $$$ for it. I paid 170 for mine including shipping. However, it came with all of the books, tube guides that go up into the late 80s, and all adapters except for the large color, which a member here sent me. I believe it was money well spent.

There's a nice one identical to mine in the same condition right now on ebay. Its missing the newer color adapters so it may go for less than what I paid.
http://cgi.ebay.com/Vintage-Beltron-...QQcmdZViewItem

If you have to have one now and are only in need to test black and white CRTs, I have an old B&K 400 that you can have, for the cost of shipping.

[fsjonsey]

Well, someone must have put a HUGE bid on that cabinet and tube on epay. I got up to $45 and and it was still too low. The B&K 465 wont work with modern tubes, only delta gun CRTs, or will it?

[Eric H]

Originally Posted by fsjonsey

Well, someone must have put a HUGE bid on that cabinet and tube on epay. I got up to $45 and and it was still too low. The B&K 465 wont work with modern tubes, only delta gun CRTs, or will it?

The bidder is "dtr_strangelove"
Could this be AK's own Dr Strangelove?

[Eric H]

I have sitting in my garage a junk 17" GE, care to guess what CRT it uses!

The tube checked really good as I recall, it's yours for shipping if you want it.