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Lightning Struck BPL Two-In-One Model CWX-69 Restored

By on December 18, 2019
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bpl audio repair

This set was bought by me from BPL, where I was employed for almost 20 years. BPL had allowed certain fringe benefits like supplying its audio/video products at drastically reduced prices to its employees. This was such a set. It was serving me well, until I moved to my home town, Irinjalakuda, Kerala, India, where lightning strikes are quite common. This set alone had suffered lightning strikes 3 times! First time when it got struck, I had to not only restore cut tracks at many places, but also replace all the ICs in the set, including the STK! But I did all that and restored it back. The next year also, it got affected, though the damages were minimal and again I brought it back to working condition. It got struck again after a couple of years and that time, it was very minimal; only a resistor in the radio aerial section had got burnt!




This year, recently again the Radio went dead during the monsoon season, probably another lightning strike! So, when I got some free time, I took this up, opened and cleaned the inside thoroughly, dismantled the whole set for complete maintenance and service. I observed charred/broken components on the board, indicating another attack on this lightning-monger set! The MW Coil was open (I hand wound it again this time, picture of which is given below), the AM/FM IC was defective (no signal came out from it, when checked;) the Varactor Diode had its leg missing as it was burnt off, the 0.047F/5.5V capacitor (for retention of Tuning preset memory in power off mode) got burnt etc.:

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Well, laughing to myself on the repeated attacks on this set like some vengeance by the ‘Thunder Devil’ (LOL), I patiently replaced all the components one by one. As I had replaced almost all electrolytic capacitors in this set during my previous service, I left it after checking ESRs of these at random. Provided belts on the Tape Recorder. Reassembled the set and played Tapes and it worked well. In the Radio, only FM worked very well. AM was dead as the handwound coil did not work. But I had no time to do trials on it and so left it to be solved at a later time (perhaps another ‘lucky’ lightning attack!)




Since STK ICs are known speaker killers, when gets shorted, I decided to add one Speaker Protection Circuit on this Set. I had already done some modifications in this set long time back, to add Line Out at the rear, which you can see on the second picture at the beginning of this article. I imported a ready DIY speaker protection kit from Ali Express, assembled, provided separate power supply to it and fixed it inside the Amp, which had plenty of space! Provided one more 12V Regulator on this supply, apart from the two already it had in the secondary of the main power supply. I also added a cooling fan which I fixed on the Heat Zinc of the Amp.

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Applied power and checked the set and found it to be working very well, indicating another miracle survival! The FM was too good! The curtain was drawn on this service, throwing open a few more areas for the ‘Lightning Devil’ to strike, if at all it was getting bored by damaging same places repeatedly! (LOL)

And, of-course nothing could stop the ‘satisfaction’ from jumping to its collection bag!

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Jovial tail piece: When I demanded a sum of Rs.1,000 to my wife asking her to pay for the services done on this set, she agreed smilingly, and replied that she would pay me later. Then came to me later saying that our BPL set got repaired and the ‘serviceman’ wanted Rs.2,000 to be paid! So, I asked for trouble! Well, we should never try to play with ladies, who almost all the time outsmart men! Another lesson learnt! (Series of LOL)

This article was prepared for you by Parasuraman Subramanian from India. He is 69 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/found-a-diode-shorted-in-computer-smps/

 

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18 Comments

  1. Tim Waldner

    December 18, 2019 at 9:54 pm

    Great job on the continued repair of this system. I assume u have the schematics for everything.
    Can’t stop laughing about ur team’s sense of humor!

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:25 am

      I do not have a schematic. I downloaded the data sheet of each and every IC when I had to replace it and followed the application circuit wherever it was available.

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  2. Albert van Bemmelen

    December 18, 2019 at 10:26 pm

    I think you better should prevent these lightning strikes from damaging the inputs of your device over and over again!
    For the speaker protection I use PTC elements in serie with my bass speakers from https://www.lautsprechershop.de/hifi/ptc_en.htm
    At least they prevent the over-current within about 3.5 seconds from burning the coils.

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 20, 2019 at 12:23 am

      Good suggestion. Have made note of for application in future. Many thanks!

      Likes(1)Dislikes(0)
  3. Robert Calk Jr.

    December 19, 2019 at 7:49 am

    Good job, Parasuraman! I do not play around with lightning. Whenever we have thunderstorms, I disconnect all of my equipment from the wall.
    We have a saying here in the USA, "If momma ain't happy, nobody is happy!" It is better to keep momma happy! LOL!

    Likes(4)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:29 am

      The problem is we cannot unplug each and every device, whenever we go out for a short while. Many attacks have come during that time! Once or twice, even small portion of plaster of the wall also got burst. We, in Kerala, live among such risks and are used to it.

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      • Robert Calk Jr.

        December 22, 2019 at 9:23 am

        I have my equipment plugged into 3 different terminal strips. So I just disconnect the terminal strips from the wall. You don't use terminal strips?

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        • Parasuraman S

          December 22, 2019 at 11:55 pm

          I just cannot understand what's terminal strip! But if that's something like the power plug69531947833, yes, we have. But disconnecting and reconnecting it two to three times in a day during the monsoon season, is impractical!

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  4. beh

    December 19, 2019 at 11:37 am

    Good job & well done

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:30 am

      Thanks Beh!

      Likes(0)Dislikes(0)
  5. Mark

    December 20, 2019 at 5:19 am

    Your wife sounds like a smart lady!

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:41 am

      Yes, she is very smart and also very humorous. Twists and turns the words while speaking for humor! For example, she will come and ask in our mother tongue, whether coffee is 'enough' for me or tea is required. As I prefer coffee always, I would say coffee is 'enough!' Then nothing will come from her. And when asked, she would laughingly say 'you said coffee is enough (with the other meaning) and tea is not required and laugh. She has many such tricks up her sleeves! Prefers practical jokes too! As we two are living alone, with our children living in other cities, we used to play around like school kids, without any hesitation. We are kids mentally (LOL)

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  6. Waleed Rishmawi

    December 20, 2019 at 5:13 pm

    man, that is a lot of evil attack against you. you do not have lightning protections installed at your house? well, look to the bright side, you getting a lot of experience dealing with the same device. LOL.
    I am glad you are safe and the device is up and running again. keep up the good work. have a blessed day

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:44 am

      Lightning protection is not good enough here. Yes, you are right, the set is giving me a lot more chances to learn, helped by the nature!

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  7. Yogesh Panchal

    December 21, 2019 at 3:35 pm

    True Repair skills and dedication sir.

    Likes(1)Dislikes(0)
    • Parasuraman S

      December 22, 2019 at 8:45 am

      Many thanks, Yogesh!

      Likes(0)Dislikes(0)
  8. Bennett

    April 21, 2020 at 7:32 pm

    Hello Sir, I had a CWX59 with me. The cassette deck was damaged and not working. I was using it as an amp. but later the amp unit was sold out to someone by my dad. i still have the speakers of this unit with me. The speakers of CWX59 are smaller compared to the CWX69. The speaker comes with a woofer and a tweater. I dont want to give away this awosome speaker unit, would like to buy an assembled amp for this speaker. can you sujjest me the power rating for the amp i need to buy. I am from the state of Kerala.

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  9. Nandan , 7093396460

    June 11, 2020 at 12:11 am

    Sir, Absolutely stunned to see your knowledge. I also own CWX79 since 1996. In 2010 it's remote got damaged and I'm missing the motorised circular volume control knob movement with red LED on it. In lockdown period, ihv opened unit for cleaning. By mistake some wire got loose or due to cotton cloth with Colin got touched on Radio Pcb & now LCD display is not working. Fortunately Radio is working but not able to see digits. Sir, if you know any specific person/service station in Hyderabad, Plz let me know. Thanks a lot in advance. Regards... Wishing great life for you and ur Bpl Cwx69.....

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