Rare Case Of SMPS Transformer Primary Open Found In SONY DVD Player Model DVP-SR200P
This DVD player was brought by a regular customer along with a tape deck. The complaint reported was that this was not used for a long time and when he took it up to play and gave power, there was a loud noise and the MCB in the house tripped. A clear case of power supply failure. I opened the DVD player and did a thorough cleaning of inside and observed that the primary section of the SMPS was charred.
The TNY176PN IC had burst and there was a hole on its side. Let us have a look at a few pictures, before we proceed further on the report of restoration work done:
The fuse was blown, the rectifier diodes were short, and the run DC diode was short. I removed all the defective components from the board and then checked the SMPS transformer with my Ring Tester and found it open. I checked it again using my Analogue as well as Digital Multimeters to make sure there were no mistakes in my finding, as it was a very rare case. Then I aborted my attempt to revive the board and went for a readily available replacement PS Board from the market.
Then studied the 5V/Ground/12V arrangement on the mother board so as to connect it properly. I removed the base of the connector from the old PS board and that of the new PS Board, then soldered the connector to the new board to match the markings on the mother board. Let us have a look at this very important part of our work:
The 5 pin connector had only two 5V, two grounds and one 12V and the -12V was not used in this set. After this, I fixed the new PS Board with only one screw and inserted a fiber washer and inserted non-conducting sheet under it to avoid contact of live parts with the chassis. (I had also retouched the solder points on the new board) Applied power and once again checked and ensured that the voltages were as marked and there were no man-made mistakes.
Then inserted the connector, after switching the power off and waiting for voltage to drop to zero. I was glad to see that the player started working with ‘load’ display. I forgot to mention that I had cleaned the eye unit using a cotton bud with a drop of IPA on it. Let us have a look at the player working along with a couple of pictures of both sides of mother board:
Then I connected the player to my table top 4” B/W TV and played the CD fully a couple of times to ensure that it worked very well. Mission accomplished with lesson learnt and a bulgy satisfaction was swallowed by the avaricious collection bag without showing any mercy! (LOL)
This article was prepared for you by Parasuraman Subramanian from India. He is 74 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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Albert van Bemmelen
February 9, 2025 at 5:22 pm
Nice to know that in these cases you chose the easy way by simply replacing the defect power board with a brandnew power module, and didn't go as far as rewinding the open transformer coil too. Although I hardly think that you learnt a lesson here because you had much harder repairs before that were no match for you either dear Parasuraman?
Those wires on the 5 pin connector in the photo maybe also could have given some hotmelt to keep them from bending avoiding short circuiting with each other? Because they did look very close to each other without any insulation on their metal pins?
Parasuraman S
February 9, 2025 at 10:56 pm
Many thanks for your expert in depth analytical comments! Yes, the repair was easier! The connectors were covered with rubber compound and it skipped my mind when writing the article as I had not clicked a snap of it! Sorry, dear!
Waleed Rishmawi
February 9, 2025 at 9:23 pm
Good repair but what caused the fault to happen? Sitting there without being used does not cause it to blow. Have a blessed day.
Parasuraman S
February 9, 2025 at 10:57 pm
Fugus formation and resultant condensation, water vapour etc.
Dennis Breda
February 10, 2025 at 7:10 am
Thank you for the post.
Parasuraman S
February 10, 2025 at 12:12 pm
Many thanks!
Mark J
February 10, 2025 at 8:16 am
Parasuraman anther great repair. Did you find out what caused it to trip the MCB?
Parasuraman S
February 10, 2025 at 12:14 pm
Sudden shorting of SMPS might have caused the mcb trip. Many thanks, dear Mark! May God bless you!
MUYKIT
February 10, 2025 at 11:29 pm
Undoubtedly a high degree of expertise repair. The commonality of power ICs in DVDs is flat rectangular 8 pin. The similarity of their failure is bursting. I think fans in FAKE DVDs provided helpful cooling.
Parasuraman S
February 11, 2025 at 10:16 am
The power supply in a DVD player is not rated to handle a load of a fan too. It might either fail or drop down because of the excess load. I have tried that and it did not work out well. Thanks!
Mendis
February 11, 2025 at 4:43 pm
Excellent your effort
Parasuraman S
February 12, 2025 at 8:30 pm
Many thanks!
Hollis LuQuette
February 11, 2025 at 7:54 pm
Smooth move going with another power supply . I have one similar to that one that is not acting right . I will be doing an article on it soon and get it to Jestin .......
Parasuraman S
February 12, 2025 at 8:30 pm
Good! Await to read it! Thanks!
Yogesh Panchal
February 12, 2025 at 4:24 pm
Good Job! Sir,
Series Lamp is the best & safe tool to use on the bench.
Parasuraman S
February 12, 2025 at 8:31 pm
Yes, the saviour always! Thanks!
Justice
February 12, 2025 at 7:45 pm
Thanks once again for this article. Forever learning !
Parasuraman S
February 12, 2025 at 8:31 pm
Glad to know it was useful! Many thanks!