Comments on: No Power In Water Filter Machine Repaired

By: Suranga Electronics

Suranga Electronics — Wed, 06 Jan 2016 08:46:54 +0000

This is not the first repair. I have repaired this same type of power supply more than 50 units within one year. All units the defective part was 82 ohm resistor only. This is a common fault. I have used the ceramic type of resistor as replacement and so far not even one unit have problem again.

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By: baishag

baishag — Tue, 05 Jan 2016 05:07:15 +0000

Thank u so much.. Excellent explanation

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By: Gary Gemmell

Gary Gemmell — Tue, 05 Jan 2016 04:29:27 +0000

You should teach electronics - you have a good grasp of explaining in a simple way with good photos and logical , stepwise refinement!

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By: Henrique J. G. Ulbrich

Henrique J. G. Ulbrich — Mon, 04 Jan 2016 15:31:38 +0000

Problems with resistors generally means "toasted resistors". So, a resistor that simply open with no more apparent cause is quite rare. And unique: no more bad components found! Indeed, a different repair work!

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By: Parasuraman S

Parasuraman S — Mon, 04 Jan 2016 13:52:51 +0000

Excellent explanation! Good Job!

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By: Paris Azis

Paris Azis — Mon, 04 Jan 2016 12:36:58 +0000

Hey Suranga

Good job. Well, this is a typical failure in transformerless PSUs (: capacitive input ones). Next to this case (the input resistor failure) the most common is the short-circuited zener diode (I guess ZD 1 in the photo you provided) including some times the filtering el cap. Due to the nature of these power supplies the mains rectifiers fail very rarely! The little magic beyond this is that they work in a “constant current” mode rather than in “constant voltage”. In most cases designers do not even use a fuse based on that…
Another important thing is that this “inrush current limiting” resistor in their input should always be a “flame retardant” type, for a reason which needs no further explanation! But don’t worry! The one you used (an appropriate type of Matsushita Electric, as I see their logo on the replacement resistor) meets fully this requirement!
I put this comment here just because many technicians put any resistor that comes in their hands for sensitive stages like this. And this reflects both their lack of knowledge and (worse than that) lack of responsibility about their work…So, good for you!

Best Regards

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By: Yogesh Panchal

Yogesh Panchal — Mon, 04 Jan 2016 08:31:19 +0000

Good Job! Suranga,
with good image quality photo.

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By: Albert van Bemmelen

Albert van Bemmelen — Mon, 04 Jan 2016 08:16:02 +0000

Finding the cause in this Fuzzy controlled device wasn't clear at first, which makes this also a kind of Fuzzy repair (LOL). But professional as always!

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By: Ehsan Murad

Ehsan Murad — Mon, 04 Jan 2016 04:13:30 +0000

Thank you . Nice step by step directions

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