Servicing Toshiba CD/USB Radio Cassette Recorder
This set belonged to one my colleagues in the Hospital and was brought to me with the complaint that it became dead after a sudden surge of voltage in their house. I carried it home and checked the power plug first, as I could see that the plug was larger in size and had its ‘belly bottom’ filled up with a Fuse. The fuse was open. That seemed to be reassuring until I checked the primary of the Transformer, which was also open!
So, I opened the back cover and ensured that the transformer had blown. Removed the Transformer and gave it for rewinding. You can see the inside of the set:
Did a general cleaning without dismantling or disturbing on the Radio/CD or Cassette side. Checked the set using my desk top power supply and found it to be working very well. CD/USB /Radio and Cassette worked without any hitch.
Got back the Transformer after rewinding. It showed 8V AC, which will produce around 12V DC, and it will get regulated to 9V DC by the circuit in the power supply. The set worked super fine. Tested it for a few hours on all modes and passed the quality test.
Put back the fixing screws and delivered it back to her after demonstrating all functions. A job completed quickly and satisfactorily sans the adventurous thrills!
This article was prepared for you by Parasuraman Subramanian from India. He is 68 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:
https://jestineyong.com/servicing-philips-ctv/
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Albert van Bemmelen
March 26, 2018 at 9:42 pm
I keep wondering how easy it is in your country to fix transformers. And also how quickly that service can be accomplished is something that is greatly missed in my country (and in many more countries I am sure). I sure would like to know more about the equipment they use and how exactly it is done. Such a task would cost you probably an arm and a leg in my country on labor cost alone?
Parasuraman S
March 28, 2018 at 6:38 am
They have a small coil winding machine. First they dismantle the transformer. Remove the outer metal cover, disengage the cores one by one and take out the coil. Then they remove the wire, during the process of which, number of turns are counted either in the machine itself or manually. Then gauge is checked correctly. Since in almost all cases, only the primary is open, they leave the secondary in the coil itself. Then the primary is rewound on the machine matching the number of counts. In many cases, if we tell them the AC output and Ampere required, they will make a new one and give, matching exactly or rewinding on using the old cores. The cost is also very cheap! (Many times we just have to wait and they will do it in front of us!) After that the transformer is dipped in varnish and dried in sun-light.
Albert van Bemmelen
March 30, 2018 at 12:18 am
Very time consuming these transformer repairs no doubt Parasuraman. Still very unique and a unbelievable quick service! And maybe it is easier if they just remove the old wire and measure its wire length instead of counting the number of turns. Then the same coil can be rewound by using the exact same wire thickness and wire length without knowing the numbercounts I guess?
Parasuraman
April 1, 2018 at 6:47 am
That's time consuming and intricate. The wires sometime get cut or entangled! I have been doing this gauge and length matching for IFTs of radios. But these AC transformer wires might touch over 2000 to 2500 turns!
Henrique Jorge Guimarães Ulbrich
March 26, 2018 at 10:30 pm
Hi, Parasuraman, thanks for sharing. I became curious about the "larger plug with its ‘belly bottom’ filled up with a fuse.
Parasuraman S
March 28, 2018 at 6:31 am
Kindly visit this link to see a similar plug. The one with the set was total black and we may have to observe closely to see the lid of the fuse. https://www.bing.com/images/search?view=detailV2&ccid=JNIdqfq5&id=F454E8F1478E0A02B7E21FFE7B04BD2E20BB4874&thid=OIP.JNIdqfq5UAsm1TLlKpS9igHaHa&mediaurl=http%3a%2f%2fwww.kenable.co.uk%2fimages%2ffig_8_plug_uk_3_pin.jpg&exph=1000&expw=1000&q=Three+Pin+Plug+UK&simid=607999103105765043&selectedIndex=15&ajaxhist=0
Humberto
March 26, 2018 at 11:42 pm
Hi Parasuraman, you have saved another appliance from the dump.
Robert Calk
March 26, 2018 at 11:54 pm
Good job, Parasuraman.
asi
March 27, 2018 at 2:09 pm
sir
why dont you teach basics how to repair a electronics products to those are new ?
Parasuraman S
March 28, 2018 at 6:21 am
Buy some basic books from Jestine Yong. Kindly go through his library.
Suranga Electronics
March 27, 2018 at 6:22 pm
Mr, Parasuraman,
Good Audio Repair Job.
and Very user friendly Mini-SET,
Amir
January 19, 2021 at 3:06 am
Sir my fm in not working please help