ON-OFF Volume Control Found Broken In SONASHI USB-8 Band Radio-SRR89
This radio was brought by a new customer (a super senior citizen living close by), recommended by one of my regulars. The complaint was that the on/off switch was intermittently working. I opened the set and was surprised to see that it was very clean inside!
Let us have a look at the inside of this 8 band radio with USB & Bluetooth connections and see how it used a single chip board with an internal rechargeable battery:
I checked the on/off-volume switch and found that it had developed a crack of the case and it was not making proper contacts. I removed it, which came out in pieces and fetched a replacement later in the day. The single chip used in this radio was KT0936MB9, datasheet and video of this wonderful single chip can be found with the following links:
https://maximradio.altervista.org/kt0936m/KT0936m_b9_v2.2-english.pdf
Let us have a closer look of the IC with extract of the block diagram and pin out details, just for the sake of information:
The datasheet runs to around 44 pages with detailed information of the internal constructions and external connections required! I replaced the volume control with on/off switch (I am deliberately avoiding the use of ‘cum’ not to cause irritation to one of our eminent expert readers! (LOL) Lubricated the controls and switches and allowed the radio to work for several hours before fixing the back cover.
I did not replace the dead battery as it had only a very cheap replacement available in the market which would not even last for a few months. I informed the customer about it and he too said that it was not required. As it was not leaking or showed any tendency to leak, I left it there itself instead of removing it and finding ways for proper disposal. Here let us have a look at the broken volume control and the replacement made, to conclude this article:
For a change, no capacitors required replacement, I had to do retouch of a few dry solder joints though.
Mission accomplished and satisfaction of tiny nature 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 The Never Ending Thrill Of Repairing Radios
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