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Made An ECL82 Output Vacuum Tube Tester

By on November 13, 2020
Made An ECL82 Output Vacuum Tube Tester

how to make your own vacuum tube tester

I have quite a lot of vacuum tubes in my collection. As a few of my friends were asking for ECL82 Amplifier Output Valve, I wanted to check the conditions of around 14 of them lying with me. I chose an ATX SMPS box from my junk collections for this purpose. Drilling a hole was a challenge to me, as I was not having the right metal cutting drill bit with me. Anyhow, I bowed in fond memory of my father, who was a Mechanical Engineer and proceeded with the work.

I drew lines on top of the box so that I can have the EZ80 Rectifier Valve on one side, the ECL82 on another and the EM84 Indicator valve in the front. Then I picked up a tool which I thought might help me drill, as the metal was not very thick. The first hole made was clumsy and I nearly escaped from an injury when the case jumped out of grip and flew, luckily away from me! This was sudden and I could release my finger from the drill only a bit late! Then I changed the tool to a different one and that one was more or less ok. Here are the pictures of my first stage of operation along with the tools:

how to make your own vacuum tube tester yourself

fixing vacuum tube tester

Then next stage was fixing the valve bases. Then assembling the circuit as per diagram. I selected a Philips Radio Amp section for this purpose. I used the EL84 output Transformer as I was not having the one as per diagram, which had extra winding in the primary side. I used a 2A, 6V AC transformer for the Heaters in the Valves, which required 6.3V, being ‘E’ series of valves. Here are a few more pictures of the next stage:

make your own vacuum tube tester

vacuum tube tester parts

vacuum tube tester diagram

After checking that all connections were correct, inserted the valves in its place. As I was not having the Mains Transformer required for the EZ80 Rectifier valve, I used the one in a Telerad Radio, which was lying with me for service. Then applied power and tried. It was working so very well that I was thrilled and almost jumped with joy like a kid!

Then checked all the ECL82 valves one by one, the process of which required switching off, waiting for the valve to cool off and replace with another. Two valves were defective. Rest of them was good. Some of them excelled, which I marked. Here is a picture, which I took out of the Videos that I covered, as in the excitement, I forgot to click!

about vacuum tube checker

about vacuum tube checker and tester

Mission accomplished and satisfaction of antique type got added to the latest digital type (LOL)!

This article was prepared for you by Parasuraman Subramanian from India. He is 70 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.

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You may check on his previous repair article below:



  1. Andrew F. Ali

    November 13, 2020 at 7:10 pm

    Nice piece of work.!!

    • Parasuraman S

      November 15, 2020 at 6:10 pm

      Many thanks!

  2. Eric Rice

    November 13, 2020 at 10:09 pm

    A few things not mentioned:
    The circuit appears to be an output section for a radio?
    How did you confirm operation of the tube?
    You made no mention of the speaker or a load used to test.
    Did you have a load and tested voltage across the load?
    Did you check amperage at the load?

    I test tubes all the time with a Hickok 600A the will pass but will fail in a circuit due to micrphonics, ticking, etc., since the 82 is an output tube they rarely fail from these issues, but would like to know how you determined the grade of the tube.

    Thanks for the article,

    Rice’s Tube Amp Repair
    Sumter, SC

    • Parasuraman S

      November 15, 2020 at 6:16 pm

      1) Yes, dear, it is the output section of Philips Radio.
      2) By listening to the output to the speakers. The last picture shows the speaker.
      3) No. I did not check the amperage. But checked voltages present, which depends on the conduction of the valve. Sorry, that was not covered in the article.

      Many thanks for your detailed observation and queries!

  3. Yogesh Panchal

    November 13, 2020 at 10:38 pm

    Really exited article.I learned about valve radio 27 years back.... refreshed old memories!!!!..........

    • Parasuraman S

      November 15, 2020 at 6:16 pm

      Many thanks! Working on valves is a thrill!

      • Mike Retz

        November 23, 2020 at 6:00 am

        Hi love your description of drilling hole . My father was a tool and die man in Detroit mich. . I learned a lot from him. Those drill bits are for wood not metal . Next time if you start with small drill bit say 1/4 inch it will go a lot smoother. Next you can use a small half round file to make hole bigger or a dremel drill will go a lot faster and smoother. Make hole as big as tube socket then trace two small mounting holes for socket mounting. You can use small drill bits in dremel or any size grinding stone that you want. Available on eBay for cheap . Dremel is trade name and sold by several different manufacturers. I was tv technician for many years and carried a tube checker with me per boss to bring in xtra bucks. It was a b&k and had many sockets for different tubes . The one that wore out most was the 9 pin socket for the 6gh8 tube that was used as color oscillator UseD in aot of rca chassis . It was a HughE seller And brought in a lot of profit for shop! And rca service co. Now defunct. I git pretty good at checking tubes but was always honest with customer... I found out that you get many repeat customers when they find out they can trust you. Have a great day!! And God bless...

  4. Henrique J. G. Ulbrich

    November 14, 2020 at 12:08 am

    Thanks, Parasuraman. Good to learn about tubes. I miss it, as a started in electronics exclusively with electronic tubes (the transistor came after).

    • Parasuraman S

      November 15, 2020 at 6:17 pm

      Many thanks!

      • A L PANDIT

        November 15, 2020 at 8:10 pm

        It took be back to 1967 when I was in college and study engineering electronics with practical repairing of valve radios. EM 84 is tuning indicator, how you have used for this testing project? Enjoyed the article and your zeal for this test.

        • Parasuraman S

          November 17, 2020 at 11:07 am

          Audio signal can be fed to the Tuning Indicator valve. I had done it and has covered it in my Article on HMV Radio repair. Many thanks!

  5. Albert van Bemmelen

    November 14, 2020 at 3:29 am

    Another useful testdevice made by a well trained engineer for making it possible to easy test the good from the bad and the ugly ones!(lol).

    • Parasuraman S

      November 15, 2020 at 6:18 pm

      Enjoyed the joke very well (LOL) Many thanks!

  6. Marinko

    November 14, 2020 at 3:29 am

    Dear colleague Parasuraman,
    thank you for this article because it took me back to my young days when I started learning electronics and drawing schemes with electronic lamps (ECC, ECL, EL504).
    The first radio transmitter in the AM area was also made with lamps and a strong output. With it I had pleasant gatherings of fellow radio amateurs at a distance of up to 100 km.

    You have a wonderful job, I also had a lamp tester for graduation work in high school made with about 7 to 8 sockets, an instrument on the pointer for the consumption of heating current. I forgot some details, but I remember that I could kpt check the correctness of the lamp-- from incandescent heating to output current.
    greetings from Croatia

    • Parasuraman S

      November 15, 2020 at 6:19 pm

      Many thanks for your recalled memories and comments!

  7. Mikael Hansen

    November 14, 2020 at 5:47 am

    If nothing else a dead PC Power Supply can always make a nice case for small electronic projects.

    • Parasuraman S

      November 15, 2020 at 6:20 pm

      Yes, that's why I used the PC ATX SMPS Case! Many thanks!

  8. Bruce Saxby

    November 14, 2020 at 11:08 am

    Enjoy reading your Valve equipment restoration and related projects, shows my age..... Keep doing them.

    • Parasuraman S

      November 15, 2020 at 6:21 pm

      Many thanks for your encouraging comments!

  9. Humberto

    November 17, 2020 at 11:57 am

    Excellent Project with Vacuum Tubes.

    • Parasuraman S

      November 18, 2020 at 11:27 am

      Many thanks!

  10. Myles McDonald

    November 23, 2020 at 12:42 am

    Thank you for the article. I am starting to learn about valves, and would like to have a tester to test some common valves such as 12ax7, el84,el34,kt66,kt88, etc. Could your tester be used for this?. Nothing fancy, just a rating on good or bad tube.

    • Parasuraman S

      January 25, 2021 at 2:15 pm

      Just make a power supply and circuit suitable for these valves, studying openly available circuits. That's all! You need filament voltage extra in the transformer. All the best. (A common single tester for all these valves are not practically not possible)

  11. Joseph

    April 2, 2021 at 4:39 pm

    Hello sir.what is your opinion on. replacing rectifier tube by diodes.


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