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Chattering Relay Problem in Sony Surround System solved

By on January 19, 2016
surround sound system repair
I got one Sony Surround System TA-AV550 with the complaint that it was intermittent and crackling noise is heard inside. Tested it on my table and heard relay chattering.
As usual, I opened the set and subjected it for a thorough cleaning and visual inspection and removed the amp board  and power supply board for inspection on its reverse side:
 Chattering Relay Problem in Sony Surround System solved 234
Noticed that there were several dry solder joints on the main board, power supply board and amp board. Did a thorough retouching all the points on the board. Saw the primary power supply AC transformer was in bad shape. Checked the bridge diode and found it has leakage between the two AC inputs (See Reading on the Multimeter)
surround sound repair
I connected the Transformer to mains and allowed it to be on for a few minutes without any load on it. The reading was 0-10V AC. Noticed that the TX was getting hot, indicating partial short inside. Now the problem was to know what could be the real secondary voltage for this?  There was no free circuit diagram for this model in the web. So, I decided to take a chance with a 0-12V, 1A TX that I had in stock. Replaced 5 electrolytic capacitors, the defective bridge diode, and also the AC filter capacitors connected across the rectifiers. Since, the relay was operating on 12V, and I saw a few transistors and zener diodes which are for voltage regulations, I connected the transformer and fit it on one screw of the other large TX, as there was enough space between the power supply board and the large TX.
Switched on the set, it worked perfectly well! No more chattering of the relay or other noises!  I ran the set for a few hours, it worked just fine! Another job done satisfactorily!
surround sound repairing
This article was prepared for you by Parasuraman Subramanian from India. He is 66 years old and has more than 30 years’ experience in handling antiques equipment Valve Radio, Amps, Reel Tape Recorders and currently studying latest techs classes conduct by Kerala State Electronics Technicians’ Association. He was a BBA graduate, retired as MD of a USA company.

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You may check on his previous repair article below:



  1. beh

    January 19, 2016 at 10:23 am

    well done PARA .

  2. Robert Calk

    January 19, 2016 at 12:14 pm

    Good job, Parasuraman.

  3. Roshan Pillai

    January 19, 2016 at 1:35 pm


    Good repair article. I read that you specialize in vintage audio equipment repairs. I was planning to make a DIY vinyl record player but the tone arm assemble is a difficult thing to make. So I was thinking if you have any old non working record player that you might like to sell? I could work on it to fix it up and use it.

    • Parasuraman S

      January 19, 2016 at 9:13 pm

      Sorry dear, I do not have any of these to sell. Moreover, I never keep any of customers' removed components with me, and I ensure that these are nicely packed in a transparent cover and they take it with them. This saves me a lot of electronic waste getting collected at my place! Moreover, it increases credibility!

      • Venugopal

        January 20, 2016 at 3:56 am

        My toshiba led tv is dead.I opened the back cover.There is 2 boards.Power supply and main board.In power supply board I found an IC with 7 legs busted.I cant read the number of the IC.If you have any knowledge regarding this IC please help me.This ic is same as IC TNY 268.

        • Parasuraman S

          January 20, 2016 at 7:55 pm

          Please let me know the model number of the TV. If you search in the web with the model number and make, you may stumble upon any service manual or circuit diagram. If you are unable to get it, please use a universal module, as per directions given by Jestine Yong in his book.

  4. Suranga Electronics

    January 19, 2016 at 2:22 pm

    Good Repair... Mr,

  5. Yogesh Panchal

    January 19, 2016 at 2:24 pm

    Congratulations ! for this quick fix.

  6. Albert Hoekman, Holland

    January 19, 2016 at 6:01 pm

    Nice job, thanks for sharing.

  7. Paris Azis

    January 19, 2016 at 6:28 pm

    Good job, Parasuraman.

  8. Albert van Bemmelen

    January 19, 2016 at 7:18 pm

    Nice repair as always Parasuraman. I had a similar Relay problem in a 400 Watt Yamaha Amplifier once. Turned out to be a completely blown 80 Watt 8 Ohm Loudspeaker that only was about 0 Ohm. And why my Relay got into protective mode. (It also was burned in with black contacts already so I replaced both Speaker and relay).

  9. dicksy

    April 2, 2016 at 3:14 pm

    good repair mr Parasuraman.well done.


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