Sad Case Of An Irremovable Dial Cord Drum In SONY 2-IN-1 Model CFS1025S
This set was brought by a recently added regular customer requesting me to restore it to a working condition, as it was negligently lying in the attic and he got interested in getting such sets repaired after seeing my facility, when he got his TV repaired. This is the third set brought by him after a satisfactory service of his TV! After cleaning the inside thoroughly I moved the set to working table in a totally dismantled condition. The set was brought without its speakers and the volume & tone control knobs missing with a damaged background where the volume knob was. I accepted this only because of the label showed behind, which showed it was original Sony made in Japan. I saw signs of someone repairing it as all electrolytic capacitors were new and was amazed to meet one like me though unknown! The customer did not know about it as he got this set as a gift from someone long back and that man was no more living! I saw that the capacitor legs were cut and new capacitors soldered on to the legs in the Radio section and I did not know the real reason for it then.
After cleaning and lubrication of all controls, when I tried to turn the volume knob, I found it was stuck and did not budge to even liberal spray of CRC 2-26, though I waited for sufficient time for it to sink in. Then I had no other go but to remove it and replace it with a new one. Good that I did so, as the tracks were all found damaged in that when I could open it the next day for a possible cleaning. After retouching all points on the main board, I turned my attention to the radio board. The radio board was fit on a frame with the tuning knob, a large circular wheel fit on to the gang condenser by a screw in the middle. I tried to unscrew and realized that the screw head was completely made smooth with absolutely no grip at all! Then, I knew why the previous technician resorted to cutting the legs of all electrolytic capacitors from its legs and soldered new in its place. Just see the following pictures:
As I could not remove the knob, without which the frame would not come away, I informed the customer about it and he said that he wanted only the tape side to be made ok and asked me to leave the Radio as it was. So I took up the tape mechanism and cleaned it thoroughly, put fresh belts as the old belts had got rigidly deformed. Then played a cassette and it was found it working extremely well. I cleaned the head, pinch roller and capstan. Applied silicon grease on gear wheels taking care not to spill it on belt tracks or tape paths. Let us have a look at the test conducted keeping the board and mechanism outside:
The set used LA4598 as its amplifier with BA3420AL as the preamp. I could download the schematic from web and that helped me too.
Hope you can see the above when zoomed, if not, please don’t curse me to be doomed! (LOL) Luckily, as it turned out to be, the radio started working, except in FM mode. In FM mode, it was malfunctioning with on/off and nothing could be done. But AM side was working though there were a few crackling noises in certain places when tuning. Probably the force applied to remove the screw by the previous technician had caused damage too to the gang. I fit the boards and mechanism back in the cabinet, provided a make shift knob for the volume control (I used a gas stove knob! Ha! Ha!).
But I could not provide a knob for the tone control! Aligned the head using a master tape, for which I used my headphones. (head – head – Good rhyming, eh? Ha! Ha! Again!) Let us have a look at the set when working in radio and cassette playing modes:
Mission accomplished with satisfaction smilingly entering the collection bag!
Here is the final picture to say good bye until we meet again in another article!
PS: Can anyone guess what the sad part was for me in this work? Expect your response in the comments! I know one person would definitely give the correct answer for sure!
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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ANTHONY PATERSON
December 28, 2025 at 6:22 pm
Someone unknown, who replaced the electrolytic capicitors before the CAPACITOR KING had his opportunity.
Parasuraman S
December 28, 2025 at 9:01 pm
Ha! Ha! Enjoyed your comments! Many thanks!
Albert van Bemmelen
December 28, 2025 at 7:11 pm
A hard case repair with a large circular tuning wheel that wouldn't come off. But professionally restored to playing cassettes and AM radio again. With FM still being an issue. But now knowing that the guy - Edwin Howard Armstrong - who invented FM when AM was widely in use, was thwarted and ignored his whole live for his great 'noise-free' invention of FM. Sadly the prolonged litigation of the 'AM owners' took a toll on his health and finances, which led to a breakdown in his marriage, followed by his suicide death in 1954. Afterwards his wife won several suits and settlements.
I read that he was born on the same day (in another year) as me.
Parasuraman S
December 28, 2025 at 9:03 pm
Vow! I never knew so much about the FM inventor! Many thanks for your expert comments and info! Glad to know that two scientists share the same birthday!
Andy Shiekh
December 29, 2025 at 12:53 am
https://tubes.mit.edu/6S917/_static/2024/resources/man-of-high-fidelity.pdf
Parasuraman S
December 29, 2025 at 9:19 am
Thanks for the link!
Andy Shiekh
December 29, 2025 at 12:47 am
Man of High Fidelity: Edwin Howard Armstrong by Lawrence Lessing
Great book with a sad ending.
Parasuraman S
December 29, 2025 at 9:19 am
Many thanks!
Mark J
December 29, 2025 at 1:11 am
Parasuraman another great Radio/cassette repair. Thank you for sharing.
Parasuraman S
December 29, 2025 at 9:20 am
Many thanks, dear Mark!
Yogesh Panchal
December 30, 2025 at 5:55 pm
Good Job!Sir
I was sad to hear that someone else did your favorite job.good idea about Gas stove Knob....here i have another ideas for Knob,you can use any tooth pest tube or any other plastic caps matching the size & using M-Seal filling inside & making knob shaft Gape.
Parasuraman S
December 30, 2025 at 9:52 pm
Yes, I too have a lot of collections of caps of various sizes, and I do use them as and when necessary. Thanks for your tip on using M-Seal. Shall try that next time. Many thanks for your detailed comments!