The Never Ending Thrill Of Repairing Radios
I am sure you all will agree with me when I say that the thrill of repairing radios is something unmatched. Especially, when these are unique and leading brands, it brings nostalgia too. Here, I am going to describe two such cases, which I really enjoyed well.
CASE (1) – National Panasonic RF562 : This was brought by my colleague’s husband stating that the radio was used by his dad and it stopped working. Let us have a look at the Radio and its inside before coming to the reasons for becoming dead and the rectification done:
As you can see from the above pictures, the Radio used one AM/FM Tuning IC, another for AM/FM RF and another for the audio output. The complaint was that it was dead even after replacing the battery. I cleaned the battery contacts and tried, but still did not work. So, I checked the on/off switch built-in the volume control. It was working ok. Then I checked whether the voltage was reaching at the board.
It was not. So, checked the DC input pin, which is supposed to pass through the battery supply when a jack is not inserted. But it was not showing continuity. So, I applied CRC-20 and inserted a jack in-out a few times, upon which the radio started working. I also applied CRC-20 on the volume and tuning controls as well as the band switch. The radio worked very well on all the three bands and I was thrilled to listen to stations in all the three bands.
Case (2) – Spanio Woody:
This set belonged to an employee working in the Grocery-Bakery-Vegetable shop opposite to my house. He told me that the radio was not working and it was left unused for a long time. I opened the set and found that the Mains transformer was burnt. Since secondary voltage was not known, I got a new one done with 3V and 5V windings. The battery was dead and after replacing it and cleaning and lubricating all switches and controls, the radio, USB and Bluetooth worked very well in the set.
I fixed the new transformer and first tried 3V AC input. But that was not sufficient, as the board had an 1117-5V IC regulator in it. So connected the 5V input, upon which a DC of about 7.5V could be obtained. The charging circuit was also working fine as can be seen from the following pictures:
The last but one picture would show you the new transformer fit in place. I tested it for several hours on all bands and functions and the unit was working very well qualifying for rejoining its owner.
Double Missions accomplished filled with enthusiasm and vigor and the satisfactions got collected as usual.
This article was prepared for you by Parasuraman Subramanian from India. He is 74 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 article on Tuning Diode (VARACTOR DIODE) Found Short In PANASONIC RQ543ADS TWO-IN-ONE
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Albert van Bemmelen
December 6, 2025 at 5:01 pm
Good to see that rewinding a defect transformer is not always an option!