Made An ECL82 Output 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:
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:
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!
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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