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Sansui AU-D5 Integrated Amplifier Repair

By on October 26, 2015
amplifier repair

 

 

 

 

 

 

This amp came to me with a complaint that the protect mode is on, and all LEDs on the right channel light up.

integrated amplifier repair

As usual, opened the amp and did a thorough cleaning.

sansui amplifier repair

sansui amplifier repairing

Since the main caps were a bit bulgy, as you can see from one of the above pictures, I checked ESRs of all the Electrolytic Caps with Blue ESR meter and found many of them out.

Even the capacitance value was far below the tolerance level.  Following pictures are of 9000mfd/63V.  (I replaced these with 10,000mfd/100V caps)

blue esr meter

So decided to replace all electrolytic capacitors on the board.  Changed 56 capacitors totally.

replace e-caps

See, how the board looks after replacing the caps:

sansui amplifier board

sansui board

sansui board repair

Did lubrication of all controls and switches with Philips Switching Cleaning Oil (my old stock; this is no longer available).  Found that the rotating type speaker connectors were jammed.  So, removed it from the amplifier, dismantled each one of them and found cut wires of the speaker inside these. This is a curse with this type of connectors!

sansui connectors

Reconnected the Speaker outlets, and reassembled the PCBs, duly connecting all the wires and after visual examination for any possible mistakes, switched it on. It worked perfectly. So, put the covers back.   Just see how it started working perfectly well:

Sansui AU-D5 Integrated Amplifier repair

Another satisfactory job!

parasuraman

 

This article was prepared for you by Parasuraman Subramanian from India. He is 65 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 and presently working as Consultant Manager, Purchase & IT, in Irinjalakuda Cooperative Hospital.

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You may check on his previous repair article below:

https://www.jestineyong.com/stk-ic-tester/

 

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12 Comments

  1. AccordionTom

    October 26, 2015 at 8:54 am

    Good job! Thank you for the write-up.

    Likes(2)Dislikes(0)
  2. Mark

    October 26, 2015 at 9:01 am

    Hey Parasuraman, you are a very patient man! That is a lot of capacitors..... I hope the customer appreciates all the work you have done. Thanks for all the explanations of the repair.

    Likes(3)Dislikes(0)
  3. Muftah

    October 26, 2015 at 12:07 pm

    Good work Mr.Parasuraman.

    Likes(1)Dislikes(0)
  4. Suranga Electronics

    October 26, 2015 at 1:44 pm

    success job..

    Likes(1)Dislikes(0)
  5. Emmanuel

    October 26, 2015 at 2:12 pm

    nice job u have done. but the capacitors are much, does it means the decrease in the tolerance value is the cause of the protect light been on permanently?

    Likes(1)Dislikes(0)
  6. Yogesh Panchal

    October 26, 2015 at 2:29 pm

    Good Job sir,

    Likes(1)Dislikes(0)
  7. Albert van Bemmelen

    October 26, 2015 at 3:22 pm

    Good Job Parasuraman! It is always those degrading Electrolytes. Also in most of the defective Power Supplies the cause of Failure.

    Likes(1)Dislikes(0)
  8. Petrica

    October 26, 2015 at 4:12 pm

    Good results Mr.Parasuraman !In many situations these is best solution when a audio device go bad .Change capacitors!

    Likes(1)Dislikes(0)
  9. Andre Gopee

    October 26, 2015 at 8:59 pm

    Great Job and keep up the good work.

    Likes(1)Dislikes(0)
  10. Parasuraman S

    October 27, 2015 at 6:35 am

    My replies:

    Many thanks to all my brothers/sisters across the Globe for your supports. It indeed makes a difference!

    Electrolytic capacitors have a shelf life. These become bad over a period of time or when not in use for a very long time. The impedance gets affected since the values of these change. Normally, the circuit designs of highly professional equipment is designed to take care of such change in all round tolerances, to make the impedance balancing within the limits. But sometimes, these do happen. The best and healthy way is to replace all electrolytic capacitors in any old equipment. It is not how long we take to repair that matters, but how good we do it! That gives satisfaction and fuel to propel forward!

    Likes(3)Dislikes(0)
    • Robert Calk

      October 27, 2015 at 9:49 am

      Nice job Parasuraman. Thanks for sharing your repair with us.
      I agree with you, especially when it is a device that we really like and want to keep for as long as we can.

      Likes(1)Dislikes(0)
  11. Humberto

    October 30, 2015 at 8:29 pm

    Good repair Parasuraman, another device saved from the dump.

    Likes(1)Dislikes(0)

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