Sooo .... I am not an electronics guy (I am a machinist by trade) but I do keep a number of tube radios going and build reproduction regenerative receivers once in a while. I also have about 500 vacuum tubes ..... bought some, given some, ..... the pile just keeps getting bigger ... I am guessing about 200 are "usable".

I need a "cheap" tube tester.

I looked on e-bay and see dozens .... start at $20 and got to $1000!

This is not a main hobby for me and I don't want (and don't have) to spend more than I need to but I do want to get a decent tester.

Can anyone give me any guidance as to what I am looking for?

There is just so many and I have not idea what I am looking for in a tester.

Thanks ..... Mike

 

Beyond those in the corner drug store the tube testers I had the most experience with were the old military TV-7 series. I about had a cardiac when I just saw what they and similar were selling for. Cheap or Inexpensive does not seem to apply when it comes to really good tube testers. I want to recall several years ago in a forum a discussion focused on some newer units aimed at the audiophile market but can't recall who was making them. I believe if you could find a good working old TV-7 it would well suit your needs. Much of what you are looking for would also depend on which tubes you are looking to test? I would assume those found in any of the old receiving tube manuals which covered the basic tubes of the day.

Ron

 

I did see at TV-7 ...... working and calibrated $1,000 !!!! On ebay not working (or at least not checked) they start at around $300 and another $300 to calibrate them ( plus shipping on something that weighs as much as a boat anchor).

There is a number of others on ebay right now for $100 to $150 plus $30 - $60 shipping ... and still not selling ... 0 bidders! I just don't know which are worth bidding on .... or even making an offer on.

If I were going to make money at this or it was my only hobby, then $1K is not really that much but for someone like myself that is just going to test the odd tube, I just can't afford that. $50 to $100 plus shipping is much more in my budget.

Thanks ..... Mike

 

A final option is to roll your own if you plan to just test a limited range of tubes. Some tubes are easy to test if you know the parameters, many can be tested in circuit using a good DMM and a cheap or reasonable oscilloscope. Fortunately the old data sheets for tubes can be found online today unlike years ago when we needed a manual on the bench.

Ron

 

Sooo .... I am not an electronics guy (I am a machinist by trade) but I do keep a number of tube radios going and build reproduction regenerative receivers once in a while. I also have about 500 vacuum tubes ..... bought some, given some, ..... the pile just keeps getting bigger ... I am guessing about 200 are "usable".

I need a "cheap" tube tester.

I looked on e-bay and see dozens .... start at $20 and got to $1000!

This is not a main hobby for me and I don't want (and don't have) to spend more than I need to but I do want to get a decent tester.

Can anyone give me any guidance as to what I am looking for?

There is just so many and I have not idea what I am looking for in a tester.

Thanks ..... Mike

Look online for 'nixie' and a guy named 'Dieter'. He has a page, and he built a tube-tester for practically every tube imaginable, he may be able to help you, or even provide schematics for what he did.

 

Awesome! I will look him up!

Thanks!!!

 

If the expectations are shivering fingers only to count money and have sth very universal, then I have no a good proposals. But if the aim is to design sth cheap but effective, let use the definition region of tube.

Just let the some kind of anode voltage source give a short-safe high voltage (may be even unregulated), but it must have an ampermeter in the series with anode. In quality of load may serve the most normal Edisson (or so called Lenin`s) lamp what is condemned now in Europe and claimed to be true "calorific bomb". The gate source gives adjustable small voltage from closed up to opened gate, with control of voltmeter. Now take care about multitude of combinations on connector lamelles and voila! - if to turning up and down the gate voltage resistor one see the anode current is changing as well, the tube is sure alive. If need to measure it S mA/V, just write down the readings and calculate. If its bit more sophisticated as triode, just apply other potentials according VoltAmper graph and it will play. If want to know actual interelectrode capacitances, just measure them by another device.

Hopefully the PS for AC 6,3V is sth that every may make well winding a transformer.

 

Sooo .... I am not an electronics guy (I am a machinist by trade) but I do keep a number of tube radios going and build reproduction regenerative receivers once in a while. I also have about 500 vacuum tubes ..... bought some, given some, ..... the pile just keeps getting bigger ... I am guessing about 200 are "usable".

I need a "cheap" tube tester.

I looked on e-bay and see dozens .... start at $20 and got to $1000!

This is not a main hobby for me and I don't want (and don't have) to spend more than I need to but I do want to get a decent tester.

Can anyone give me any guidance as to what I am looking for?

There is just so many and I have not idea what I am looking for in a tester.

Thanks ..... Mike

When I built a CRT tester/rejuvenator - it was a pretty crude lash up that didn't do much more than measure unbiased cathode current.

You can start by binning all the "ghosted" tubes that someone let the vacuum out.

Most of the time - anything with in spec cathode current is worth hanging on to, other parameters are less likely to go awry. One thing you might encounter is intermittent inter electrode shorts, usually a flailing broken grid wire, a tube tester may not see that unless you disturb the tube during the test.

A manufactured instrument usually has the advantage of most tube sockets you'll ever need - I used fly leads with socket receptacles on the ends, usually silicon rubber or heat shrink tube keeps them from getting loose.

 

Hello,

There are many manuals and schematics for tube testers on the internet archive:
https://archive.org/search.php?query=tube tester&and[]=mediatype:"texts"

Bertus

 

I've got an ancient AVO valve tester which you would be welcome to except that it's here in UK and it's big and heavy
Like this one:

 

I actually have a TV-7. I've probably had it for 50 years. There are manuals on the net for it. It could probably use a few sockets replaced, but that is no small feat because the wiring is very dense. When calibrating care must be taken to use the same ohms/volt meter. If you use a 10 M input Z meter calibrate, it won't be calibrated.

There's another tube tester around the house too. Nothing at home does the weird stuff with 37V filaments that were used in TV's.

I saw recently a tester that probably works well, but you have to know what your doing to use it.

Testers that actually measure gm exist too.

 

I never bought a tube tester back when I was repairing televisions. It was just too easy to go to the local hardware or drug store. Or I would just stop in at the parts store in town on my way to or from school. There were testers all over the place.

 

Free sounds awesome but I am guessing it would cost a fortune to ship it ship it here to the US.

I would need to do a bit of homework also ... I know I would need a step down transformer (we use 120 you use 220 .... thought I do have 220 here in the house to run the water pump and electric dryer).

I think also there is a difference between US tubes (valves) and British ones.

Anyway, I will keep it in mind.

Thanks ...... Mike

PS .... I do remember when the TV died, my dad pulling out all the tubes ... taking them to the corner store ... testing them and buying replacements .... seems such a long time ago, boy have things changed

 

Nice discussion here: http://audiokarma.org/forums/index.php?threads/which-tube-tester-to-keep-539a-or-tv-7d-u.722273/

there's a pic of the insides of a TV-7.

 

PS .... I do remember when the TV died, my dad pulling out all the tubes ... taking them to the corner store ... testing them and buying replacements .... seems such a long time ago, boy have things changed

That was when there _were_ user serviceable parts inside.

The back off the TV disconnected the power cord and there was a tube placement diagram on the inside.

 

A rare find when there was a full schematic attached to a pocket on the back of the set.

There was a time where all of the filament voltages added up to 120V, so the set became transformerless. Those tubes, we (dad and I) could never test at home, so we relied on the local 7-11 convenience store. My father did the tube test and swap for people he worked with.

 

I actually have a TV-7. I've probably had it for 50 years. There are manuals on the net for it. It could probably use a few sockets replaced, but that is no small feat because the wiring is very dense. When calibrating care must be taken to use the same ohms/volt meter. If you use a 10 M input Z meter calibrate, it won't be calibrated.

There's another tube tester around the house too. Nothing at home does the weird stuff with 37V filaments that were used in TV's.

.

UK had TVs with 300mA series heater chain with P prefix tubes - the heater voltage was arranged to consume the same power as the equivalent E prefix tube 6.3V heater.

AIUI: America had 600mA heater tubes that accommodated the lower mains voltage.

In the early days - straight mains voltage filaments in rectifier tubes were fairly common in America.

 

Hmmmm ..... so it was like a string of Christmas lights ... one goes out they all go out?

Mike

 

Hmmmm ..... so it was like a string of Christmas lights ... one goes out they all go out?

Mike

Yeah, that's about it. Here is an example of a tube (valve) radio with series filaments.


The merit to the design was elimination of a transformer. The former B+ was simply derived from line voltage using the 35W4 a popular rectifier tube. Unfortunately the drawing is a little fuzzy but you get the idea. One tube filament goes and it's dark in there. Using a VOM you would start on the first filament and walk along till you found an open filament tube.

Ron

 

This review/history https://www.sarsradio.com/index_htm_files/SARStubesHickok-Dates_021917.pdf#page=9&zoom=150,55,25 may prove useful.