Don't Miss


Revived The Radio Pick Up In NATIONAL RX-FS21A Two-In-One But With A Sad End

By on October 24, 2020
radio repair

 

 

 

 

 

 

 

 

 

how to fix national radio

This set belonged to a friend living close by. It was brought to me by his son for reviving the tuner section as it was not working. As usual, my first duty was to open the set, which itself threw a challenge. The screw holes were all filled up by wasp nests made of mud, as a result of which, the screw-heads were rusted and lost its grip. I obtained permission from the customer to cut it open. I used a special screw-driver which I had sharpened like a chisel for such break-open work. Then I hammered this chisel around the screw head and broke it away from its back cover. Already the set had such broken screws in two other places, probably done by another technician, which was an indication that the set was worked on before, though it could be long back. I saw a lot and lot of dust and dirt inside the set and signs of leaving unused for a prolonged time. Fungus had attacked at a few places on the board. After blowing off the dust, dismantled the set completely.

I even removed the Transformer (it was a locally made replacement; probably due to failure of primary in the original transformer), and cleaned all the inside very neatly. After lubricating the switches and controls and operating these vigorously to enable self-cleaning, I reconnected the power supply and tried. The radio was showing signs of getting back its life and all bands were working though not well enough. So did a thorough dry solder patch up from one end to the other. I did the same on the AC inlet board also (Unfortunately, I forgot to click it when I took it out!). Then cleaned the board thoroughly using IPA, ensuring that these do not enter into coils. Then when I applied the power after reconnecting the board, all bands worked except FM. So, I knew there was a man-made problem. Located it to an overlapping solder on the FM IF coil. Removed the short. Then FM also started working very well. Incidentally, no capacitors were found bad enough for replacement! This was a surprise for me (Perhaps a disappointment as well, as I could not indulge in my favourite work!) (LOL)

how  to repair national radio

Applied solder around the TRA joint, as it was loose:

tra joint

Put back the Tape Mechanism, which was in a very good condition. When I played the tape that was in it, it worked very well, including auto stop. In fact, this mechanism was very sturdy and could take any rough handling including abuse to certain extent.

how to fix and repair national radio

radio fix

After trying it for several hours and rechecking all the functions informed the customer to come and pick up. Then I learnt sadly that my friend was hospitalized and was to undergo an emergency operation. Later I learnt that he succumbed to the illness and left this world, which was very shocking to me! He was a retired School Headmaster and was a good citizen and was always very joyful and mingled with everyone jovially. What a sad thing to happen! Unfortunately, I could not attend the funeral as my wife was undergoing Ayurvedic Treatment in a hospital, around 25 Kms away and I was staying there as a bystander to help her. Moreover, restrictions due to pandemic situation did not allow crowd of more than twenty in a funeral. Now the set is with me, and I hope one day the family will recover from their shock and take it back! Until then, I opted to keep using it daily in his fond memories!

Though the satisfaction of having done a successful work got collected, it was not with the usual enthusiasm associated with it! That is fate, something beyond the control of humans and sometimes we have to put up with such situations! There is no other go! Anyhow, should they come to take the set back, I will treat the service as a posthumous gift to my good old friend, who was senior to me by three years!

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.




Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.

P.S-If you enjoyed reading this, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!

You may check on his previous repair article below:

https://jestineyong.com/rusted-transistor-caused-numeric-computer-ups-to-become-dead/

 

Likes(49)Dislikes(0)

14 Comments

  1. Albert van Bemmelen

    October 24, 2020 at 2:32 pm

    Although it was no happy end for losing an old friend and mentor. I do hope your wife is doing okay after her Ayurveda hospital treatment. And talking about bad fate, a week ago I also suddenly lost an old friend I knew since my 1974/75 schooldays only being 60 like me. He always seemed busy never taking a rest, and no one saw this coming. There is nothing we can do about it! Being engineers we sadly only can fix devices, not people. But the fact that you provide excellent service to your local hospital is undoubtedly for the greater good!

    Likes(5)Dislikes(0)
    • Parasuraman S

      October 24, 2020 at 4:45 pm

      Yes, dear! Absolute truths!

      Likes(4)Dislikes(0)
  2. Lynn Blakely

    October 25, 2020 at 2:23 am

    Dear Parasuraman S: I had to laugh when you said"no capacitors were found bad enough for replacement! This was a surprise for me (Perhaps a disappointment as well, as I could not indulge in my favorite work!)We are quite fond of your excellent, and thorough repair episodes. We have a saying,"Its better to have a sense of humor, than no sense at all."

    Likes(3)Dislikes(0)
    • Parasuraman S

      October 25, 2020 at 7:07 pm

      Many thanks!Glad that you enjoyed reading!

      Likes(0)Dislikes(0)
  3. Humberto

    October 25, 2020 at 11:15 am

    It´s a pity your no happy end in this article, my Mom died this year, July 4th.

    Likes(1)Dislikes(0)
    • Parasuraman S

      October 25, 2020 at 7:08 pm

      Oh! Heartfelt condolences! May the departed soul rest in peace!

      Likes(0)Dislikes(0)
  4. Paris Azis

    October 26, 2020 at 2:36 am

    This is a cruel form of life’s irony Parasuraman. You saved your friend’s apparatus, while he lost his life...Anyway you did what you had to do for his sake and this is what counts! Just keep your friend in your memory. My best wishes for your wife (and family in general).

    Likes(1)Dislikes(0)
    • Parasuraman S

      October 27, 2020 at 9:12 am

      Thank you dear!

      Likes(0)Dislikes(0)
  5. Imoudu Onwumah

    October 26, 2020 at 7:05 am

    Hi sir, Sorry to take you back.In ur last article on computer ups repair,you said u substitute trans ck100 for bad st2n2907a and it works. I check the datasheet for these two transistors for compatibility,I found out they do not have same pin out.So how did u connect ck100 on board for it to work sir
    Thanks.

    Likes(1)Dislikes(0)
    • Parasuraman S

      October 27, 2020 at 9:42 am

      ST2N2907 is a PNP transistor. Please see the link here :
      Same is the case with SK100.

      CL100 is equivalent to SL100 and CK100 is equivalent to SK100. Why the datasheet shows both as NPN transistors by CIL is not known. It could be a mistake. I have checked the CK100 in Peak Atlas for type and pin configuration before I put it. The result is evident, as the UPS is still working with the customer! I have been using CL100 and CK100 in place of SL100 aand SK100. Anyhow, many many thanks for bringing this issue to highlight!

      Likes(0)Dislikes(0)
  6. Derek Nathaniel, Pakistan.

    October 26, 2020 at 6:56 pm

    May their souls rest in peace this is the stage when no one can do anything for anyone it is God's will and we all have to accept it.

    Likes(1)Dislikes(0)
    • Parasuraman S

      October 27, 2020 at 9:43 am

      Very true! Many thanks for your comments!

      Likes(0)Dislikes(0)
  7. Yogesh Panchal

    October 27, 2020 at 9:23 pm

    Sir,
    Good visual inspection skill is must when the equipment is repaired by another hand.as you stated here an overlapping solder on the FM IF coil
    this type of mistake are possible when person is doing work in hurry.

    Likes(1)Dislikes(0)
    • Parasuraman S

      October 28, 2020 at 9:10 am

      Yes, very true! It can also happen inadvertently when the angle of the soldering iron is slanting. Many thanks for your comments!

      Likes(0)Dislikes(0)

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Free Report