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Author Topic: Decided to get a tube checker  (Read 8201 times)
KA5ROW
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« Reply #15 on: December 28, 2012, 07:55:10 PM »

Still looking for a good tube tester lost out on a Hickok 6000-A on e-Bay and the Hickok 539 A is starting to get a little high. Watching a Mercury 2000 would like to know from anyone who has owned one, was it a decent tester? If I spend $300 to $500 for one, I want a good tester.

I have found some information and from what I have found Hickok is the bench setter. But I do not know where B&K, Sencore, Mercury and so fall in line.
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AC5UP
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« Reply #16 on: December 29, 2012, 06:31:04 AM »

Three things:

1)  It's spelled " Hickok ". Most of you got it right, but there have been moments...   Tongue

2)  At this stage of the game there are a buttload of variables involved in getting a 'good' deal on a tube tester. A visit to BAMA will return manuals on many models to answer questions about the theory of operation and relative sophistication of any given tester - plus - the list of tube types available for test. If the best tube tester on eBay doesn't cover tubes designed after 1953 there's a fair chance you won't be happy with it unless you're really into pre-war Zeniths.

3)  Like anything else that's used, price and condition will vary. As with the paragraph above, a great deal on a quality unit that can test every tube ever made is less a bargain if it has been dropped (hard) only once or has a tiny little problem with the power transformer........ Like an open winding. Good used tube tester transformers are a be-yatch to find.

Caveat Emptor on steroids, and do the leg work on BAMA before you buy.
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AA4HA
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« Reply #17 on: December 29, 2012, 10:36:03 AM »

Good article;

http://www.tone-lizard.com/Tube_Testers.html
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KF4ZQM
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« Reply #18 on: January 06, 2013, 04:33:13 AM »

I see this question all the time on several forums. The one thing that is seldom considered is the number of tubes each tester has testing data for. Some roll charts/data books have only a couple of hundred tubes listed. If you buy one of those, you will keep running into tubes you can't test. The tube tester I recommend is the military TV-7D because the complete tube data book is 100 pages.  The next best is the Hickok 539 B or C with 87 pages of testing data, but a nice one will cost around $1000.
The build quality of the TV-7 is also far better than any of the commercial Hickoks.
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KC4MOP
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« Reply #19 on: January 06, 2013, 05:40:33 AM »

there are some internally fragile tubes that short if you look at them funny... the same audio tube used in the Heath SB/HW series is used in some Hammond organs.  looky here, they are prone to shorting suppressor to cathode. that burns up the limiting resistor if any, the rectifier, and the power transformer.

there are also a bunch of NOS tubes that have gassed up over the years, but sitting in the tester socket for a while can degas them.

two excellent reasons to have a tube tester.  and it's not necessary to have one box to test them all, and in the caddy bind them, if you get a newer tester and an older one at the right price.

Good thought about tubes shorting and causing other damage. There would always be a plate resistor or screen resistors to limit current. Bypass caps short out too, stressing the power supply. But should not damage. Rectifier tubes can take out the transformer, but that's what fuses are for. It's folks who UP the fuse rating every time it blows that causes more damage. And they curse!
The tube tester seemed like a nice option for trying to match tubes and their ratings, maybe in a tube amplifier (sound). But for general maintenance, I never relied heavily on a tube tester, especially in RF service. It has been swap and listen or watch a 'scope pattern to see or hear change in performance or complete repair.
I keep a nice R390A going with good ole fashion electronic maintenance and usually the trouble is from tubes that sit in the caddy and made recently. The NOS stuff is flaky or maybe sitting causes problems later.
It usually can go for almost 2 yrs of 24/7 operation of this radio before something gets noisy or scratchy or sensitivity drops off. And there are actual circuit problems that require the DVM and looking at the Scheezo to make repair.
Fred
Fred
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W6EM
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« Reply #20 on: January 07, 2013, 07:53:17 PM »

Hickok 539C!

Would never part with mine....

Of all out there this is at the top of the list...TV-7 next....

600, 800 and 6000 are ok...

I think there were at least 4 versions.  TV-7/A, B, C, and D.  If you find one, and it doesn't have the tube data (manual), shoot me an email.  I have the /D model, and a like-new manual that I could copy.  mycall at arrl.net


Lee
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AC5UP
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« Reply #21 on: January 08, 2013, 02:14:01 AM »

The manual is easy to come by... Updated tube test data, too...
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KD4SBY
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« Reply #22 on: January 10, 2013, 05:36:39 PM »

Just a question, a commercial tubetester has to check almost every tube available at the time of its manufacture, but what about if you are only interested in checking a narrow set of tubes? Like only the 7 and 9 pin tubes used in the 70 and 80's, and from those, only 10 or 20 types or so. What would be involved to build your own from scratch?
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AC5UP
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« Reply #23 on: January 10, 2013, 05:58:19 PM »

The short path is that you don't build your own............. You study the tube data charts to find similar tubes then adapt the tester setup to match.

Example: http://www.nj7p.org/Common/Tube/SQL/Tube_query.php?Type=6AQ5

The 6AQ5 is a seven pin Noval base miniature tube and the electrical equivalent of the 6V6, an eight pin Octal based tube. If you can transpose the switch settings from the Octal to the Noval socket, a 6AQ5 should test the same as a 6V6.

Didja' know that a 6C4 is half of a 12AU7?

Even if you did build your own tester for 'modern' tubes you'd still need to determine the test voltages and pinouts. Same as you would on an old tester.

BTW:  Tubes developed in the 70's were relatively few and tended to be Compactrons, which makes them somewhat rare today, so there's not much point in developing a tester unless you're really in to refurbing 19" portable TV's...
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AC2EU
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« Reply #24 on: January 11, 2013, 06:55:25 AM »

Tube substitution is no doubt the way to go but with today's tube prices, this isn't such an attractive option as it once was.  

If you have only one radio..... yes, but if you have more than one..... or if you like to work on boatanchors then the tube tester becomes more attractive.

I was given a Hickok many years ago and I still find it nice to be able to go through 25 tubes in a boatanchor before investing money in new caps and resistors.  

One good thing is, after the investment, you don't have to feed it!   Grin



I agree, wholesale testing of the tubes before a project is begun is a good way to get a base line of the cost without too many surprises.
My boatanchor tester was made by the Superior company. It tests tubes just about from day 1 through the mid 60's.
It checks for gas, shorts, and relative dc transconductance. The chart has provisions for testing complex tubes with dual functions such mixers, dual triodes etc.  I do wish it had an actual transconductance measurement though.
Despite it's simplicity, it has always been spot on identifying weak or defective tubes for me.

Many of these oldies have updated charts that can be found on the internet which extends their usefulness as was the case with this one. The file was so large for mine that I had to put it in a 3 ring binder!!!


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KD0REQ
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« Reply #25 on: January 11, 2013, 09:41:11 AM »

I have a Hickok 533A to test the older stuff, and a Sencore 154A for newer stuff.  both have their advantages.  the Sencore manual actually has the steps needed to develop a test for newer type tubes, based on what you find in the spec sheet for that tube.

the special sauce is knowing what each knob, dial, and button does on your tester, and what socket pins go where. got that, use your noggin, write down the new tube recipe for the future.
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KD4SBY
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« Reply #26 on: January 29, 2013, 07:58:43 AM »

The short path is that you don't build your own............. You study the tube data charts to find similar tubes then adapt the tester setup to match.
That is hard to do if you do not have a tester. That is why I posted the question. I wanted to know what is involved in building one for checking just a dozen types or so and thus do not have to provide all kind of filament voltages and sockets.
I also do not know how to read tube specs and therefore do not know what is needed to build the necessary circuitry.
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KD0REQ
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« Reply #27 on: January 29, 2013, 10:02:42 AM »

there are one or two guys who build specialized computerized audiophool tube testers for the common preamp and power tubes in that service.

the guy who decides to use 833As for output is on his own.  there are a few. (sigh)

read the article mentioned above.  if you only care about 10 tubes and want to test a hundred of them to find the two best and move the rest on eBay, then you want the Cardamatic 123A.  throughout my childhood, I had access to one in master control of the TV station.  had access to lots of cool stuff in those days. now I have to build it, or rebuild it Wink
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AC2EU
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« Reply #28 on: January 29, 2013, 02:51:46 PM »

there are one or two guys who build specialized computerized audiophool tube testers for the common preamp and power tubes in that service.

AUDIOPHOOL !!! ROFLMAO!!  Grin
I see the money that some sites are asking for "audio tubes" and that just about describes the customers!

BTW, that "warm sound" that the tube aficionados are so fond of is nothing more than a pleasing distortion!
Technically speaking, modern solid state amps blow tube amps away in actual fidelity.
However, beauty is in the ear of the listener!
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KD0FAT
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« Reply #29 on: January 29, 2013, 05:20:28 PM »

KA5ROW started this discussion because he wanted a tube tester, and he wanted advice. Everyone on eHam has an opinion (and then some).     In My Humble Opinion:  try to find an inexpensive Hickok or Stark (the Canadian version) and learn all that you can by using the tester.  If you are planning to be a tube reseller, and you have a large inventory of vacuum tubes, then you need to have one of the best units, spend big bucks, etc, etc.  Then, you are spending the money for a top line unit to support your business.   If you were just going to test a few tubes for your favorite classic boat anchors--then either get a tester cheap, or forget it.  Instead of buying a tester, buy the tubes that you need from a reliable supplier.  I paid $65 for my old Hickok 532. I would not have bid for it at $165.  At $300 to $500 for a tester, you should consider what you really want to use the instrument for.  73,  Al
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