Fixed Broken Wheel Of Tuning Needle In National Panasonic RX-5100F
Those of you who have not seen the previous history of this unit published in September, 2015, can view this:
https://jestineyong.com/national-panasonic-rx5100-radio-cassette-repaired/ [I have now included better pictures without re-sizing in this article, for those who are interested to see the inside clearly] This unit was brought back to me in September, 2020, exactly after FIVE YEARS of use, with the complaint that the needle was stuck at the left side and it does not come out. I presumed it could be due to a loose cord or overlapped winding of cord. Anyhow, I opened the set and did a thorough cleaning of inside using blower and dismantled the Tuner PCB.
I observed that the cord on the twin-sized wheel that supplies it to the needle and collects it back, had come out of its lower large sized wheel and got wound on the smaller portion.
Then noticed that one of the two tips that hold the cord to the large wheel was broken, as a result of which, it got slipped and got wound on the other. So, there was no grip and the wheel was rotating without pulling the cord! I am giving below a picture of another similar wheel near the drum for you all to have a comparison, along with the broken one:
So, I used my hot soldering iron to insert two cut steel pins to its place. It went in and held firmly as the wheel was solid and not hollow. Then kept the needle at the extreme left and routed the cord through the metal tips. Then the needle was moving left and right very well.
After trying it a few times, applied Fevibond (a rubber compound) so that it does not slip out. Also cut extra length of the tips so that it does not cause any obstruction.
Put back the Tuner PCB and its connectors to the main board. Tried the tuner and it was working very well. Even the tape was working very well. Assembled the set back and allowed it to run for several hours before calling the customer to come and collect it! (That was a lot of ‘C’ in sequence (LOL)) Satisfaction was only happy to jump to its collection bag! Here is the proof for final working; look at the red LED Sound Level Indicator in the middle, above cassette door!
This article was prepared for you by Parasuraman Subramanian from India. He is 70 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: