Restoring Antique Valve Amplifier Ahuja TM-50
This Ahuja Valve Amp was gifted to me by one of my friends, looking at my interest in collecting antique pieces. It was lying in one corner for many years without even opening. Though many customers asked whether I could restore it and give it, I was turning them away. However, having reached almost 70 years, and as there is none in my house who will take over or continue this work, I decided to do some ‘load-shedding!’
So, when one of my regular customers, who has bought a few items in the past, was repeatedly asking for it, I decided to open it and see the condition. I cleaned the set thoroughly. In all such restorations, it is mandatory to check and replace the Tank Capacitor, which I did and ensured that the power supply was safe enough to switch on. Found a couple of Valves missing. Mains On/Off switch was defective. Replaced the switch and looking at the bottom circuit, assumed what could be the valve number and placed two EL84 Valves. Switched on and it was showing life. But another ECC83 had a crack on it.
Replaced that also and I got a hopeful output now. So, combed the bottom of the Amp for defective components. Replaced rest of the electrolytic capacitors, one open resistor and one potentiometer which was found defective. Provided a missing knob, and a new mains cord in place of a half cut. The set had a nice lay-out and arrangement of components. The (-) points of Electrolytic Capacitors were all uniformly arranged on one side! The trouble shooting was very, very easy! This shows the class of the Manufacturer and how principled they were! Cleaned and lubricated all the controls and valve bases.
Switched on the set and it was working with superb output! Though I also replaced input of Mic-3 with the latest RC socket, I forgot to click when all work was finished! So excited was I! (In mono sets, whenever I provide a new input, I give one each for Left and Right channel, interconnecting these with a 0.1/400V polyester cap.) In fact, I was a bit reluctant to part with the set, but forced myself to give it off, as a part of my commitment and maintaining credibility!
This job was more than ready to jump into the satisfaction bag, and I gladly let it do!
This article was prepared for you by Parasuraman Subramanian from India. He is 69 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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