13007 Power Transistor, Faulty Diodes and a Capacitor Found In Self Made LED Porch Light
This is a generally available Power Supply that can take around 2A load usually used for LED Serial Lights. I had bought one along with a ready made strip of LED lights for use in my Car Porch. This has been working fine for the last two years. But suddenly went dead, tripping the MCB. So removed it and checked what went wrong, after thorough cleaning. I had provided grill to prevent any gecko doing any exploration. Though the grill was having very small pores, the unit was almost packed with very small dead insects, which find its way through.
On opening and checking the components on the board, I could see that the fuse was cracked; all the four rectifier diodes were short along with the 13007 transistor. The tank capacitor, 33/450V was showing zero ESR and on removing it, I could see that it was rusted and corroded at one pin, due to leakage. These were indications of high voltage surge and moisture formation. Replaced the defective components and checked for any more defects and could not find any.
Since exact size of fuse was not available, used a slightly large one, covering it with a protective sleeve and marking its value on top of it. Powered the PS through a series bulb and found it to be working. So assembled it back and retested it.
Plugged it back on the car porch and checked it again.
These are the defective components:
Work completed and added to my ‘SL’!
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/fungus-attach-in-vartech-oscilloscope/
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Robert Calk Jr.
December 18, 2018 at 12:45 pm
Good job, Parasuraman.
Paris Azis
December 18, 2018 at 4:20 pm
Hello Parasuraman. Good job. I have also repaired plenty of these power supplies. In fact I have upgraded the most of them for their higher longevity possible. Well, I like that "Rabicon" cap! Very close to "Rubicon" but, of course, not related to it in terms of reliability and general quality...!! Just another "eye catching-tricking" cap brand!
ALAN WILSON
December 18, 2018 at 5:03 pm
Is that REALLY a RABYCON cap!? Surely a copy of a well-known make (!) and possibly the cause of the failure of so many components?
I've heard of 'rabies', that's quite a bad thing too!
Thanks to all contributors, I am a regular visitor to this forum and I am always in awe of the amount of knowledge shared on it. My ambition would be to have a fraction of the knowledge shared here. I'll let you know my nickname which might just tell you my level, ie 'Dabbler'....
Pity you're not closer Jestine or I'd surely take advantage of your services in training!
Sorry long-winded, but had to thank you all again.
Very best wishes. Alan
Augustine
December 20, 2018 at 5:02 pm
counterfeit capacitor, which were low quality...
the rubber bungs is one tell tale... and rubycon... instead of rabycon
Albert van Bemmelen
December 18, 2018 at 6:39 pm
Luckily in my country we never have had to deal with geckos or other short circuiting causing living animals. Owners of cars however have to watch for eaten up wires and tubes by stone-marten or beech marten who seek up the warmth of the engine.
Mason Sarles
December 19, 2018 at 10:58 pm
Thank you for sharing your work. I really reading of your repairs. That was an ugly leaky capacitor.
Thank you again,
Mason
Texas
beh
December 20, 2018 at 12:22 am
well done Prasuraman and thanks.
Albert Zwezwe
November 21, 2019 at 2:20 am
Wow I like it keep up with the good work