Unbelievable! Shorted  E-Cap In Sony DVD Hi-Fi

By on January 21, 2019
sony hi fi system repair

 

 

 

 

 

sony hi fi system repair

This  Sony DVD Hi-Fi came in with the complaint of no power and surely the standby LED would not light up. The first thing I did was to open up the cover and head straight to the power section. This model still use the linear transformer and the main fuse did not blow.




If it blows into dark color, this means there is a serious short circuit.

sony hi fi system fix

sony hi fi board repair

I checked the incoming 230 volt up till the transformer primary but there was no  secondary output voltage. There could be two reasons when there is supply voltage input but totally zero volt output. The first cause would be the  primary winding open circuit. For your information, secondary winding rarely open circuit. Next cause was there is a shorted component along the output DC line to ground or the mainboard is shorted.




When I placed my ohmmeter to DC line and  ground I saw that it has very low ohm reading either way indicating there was a short circuit. I checked on the secondary filter  capacitor first (1000uf 25 volt). By removing the filter cap I noticed there was no longer short circuit thus this confirmed the e-cap is the cause of the short circuit.

sony hi fi board repairing

I tested the suspect e-cap and it was proven to have short circuit-see the photo below:

how to repair sony hi fi

Usually when an e-cap is bad, it is either ESR ohm very high or the capacitance value out but this e-cap is shorted (considered zero Ohm already).

shorted 1000uf 25 volt cap

Just to test out if the shorted e-cap is the only cause  of the problem, I put in a 470uf 25 volt for testing the output again.

how to fix sony hi fi

As expected, the power came back (see the two photos below).

sony hi fi standby repair

sony hi fi standby fix

Conclusion- Assuming if the secondary output e-cap is good then I need to check and troubleshoot on the mainboard to locate the short circuit. For those of you who wants to be good in checking electronic components, I can recommend Jestine Yong’s ebook HERE.

suranga

This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.




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Note: You may check out his previous post in the below links:

http://jestineyong.com/no-display-in-tv-due-to-eeprom-ic-fault/

 

 

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11 Comments

  1. Waleed Rishmawi

    January 21, 2019 at 2:36 pm

    yes, I have seen a lot of equipment with the same issues. a job well done on the repair. have a blessed day and thanks for sharing

    Likes(5)Dislikes(1)
  2. Parasuraman S

    January 21, 2019 at 2:53 pm

    Marvelous troubleshooting! Very rare to see electrolytic capacitor shorting!

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

    January 21, 2019 at 3:46 pm

    Pro job Suranga! Those d@#mn e-caps!

    Likes(1)Dislikes(0)
  4. Menahem Yachad

    January 21, 2019 at 4:57 pm

    I have seen shorted e-caps very often.
    As technicians, we should be ready for anything.

    When I do an ESR check of all e-caps on a PCB, if I see any e-cap with suspiciously LOW ESR, I immediately do a secondary check on that e-cap with my Ohm-Meter to determine whether the e-cap is shorted.

    The ESR meter is an excellent tool, but it cannot diagnose all faults, and this is one one the faults which the ESR meter will give a CAP-OK result - in fact the cap is NOT OK.

    Likes(5)Dislikes(0)
  5. Robert Calk Jr.

    January 21, 2019 at 6:34 pm

    Good job, Suranga.

    Likes(2)Dislikes(0)
  6. Mark

    January 22, 2019 at 11:26 am

    Thanks Suranga, I'll keep that in mind 🙂

    Likes(1)Dislikes(0)
  7. juackim machona

    January 22, 2019 at 11:27 am

    job we'll done thanx for sharing

    Likes(1)Dislikes(0)
  8. BEH

    January 22, 2019 at 6:55 pm

    WELL DONE SURANGA.

    Likes(0)Dislikes(0)
  9. Humberto

    January 28, 2019 at 5:23 am

    Wow! e-caps as usual nowadays. But this time it was shorted.

    Likes(0)Dislikes(0)
  10. Luciano Khware

    January 29, 2019 at 4:08 am

    NIce work sir. Keep it up!

    Likes(0)Dislikes(0)
  11. Kuuderb

    January 31, 2019 at 6:07 am

    Sir,thanks for sharing your knownlege with us. As for me,your work actually help me alot in the fielt of reparing.Please keep it up.

    Likes(0)Dislikes(0)

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