12V Power Supply Failure Follow Up

This power supply seems to have become a bit of a star on my channel. It quit working shortly after being put into service and then was repaired. After a while longer it failed again with a different fault. In this video I fix the fault that I discovered in the last video. It will be interesting to see how long it lasts for this time.

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[mantapwow]

I use Omron power supply for almost three years non-stop, it never fail. Power supply is essential, it's the heart that supply power to the system, don't cheapening out.

[miks]

Well done, its very satisfying when you bring something back to life

[bardenegri]

I have a meanwell 12v supply for the lab and it's been a real champ so far.

[MendotaTech]

That's what you call a "FIAT" Power Supply. Fix it Again Tony! badum tssss....

[Zebra_Paw]

the brand doesn't mean anything, they just bought it and then resold it. Those power supplies are very good when you don't use it at their full rating, for example if you need 12v 10 amps you should buy a 15 or 20 amps version!

[Mraidi-Amine]

Hi bro, i've a problem with my power supply 12v 10 A, it has som knoking nois + 0V out, plz can u help me, i cheked all of compnnt but they work just fine, thnx bro.

[OldSkoolF]

ROFL... If I had a dollar for every lower spec part I've put in repairs around the shop... Never had an issue!

[mrJety]

If you wanna repair this board for good, try using a flux capacitor.

[Darieee]

Hooly shit .. I bought one of those for a Mac Cube (28v 7<<< A) .. will be replacing all the caps preemptively in that case ..

Also I'd assume once you change all the dirt cheap crap parts ... it should start working more reliably

[iblesbosuok]

Put additional TVS14391 to prevent voltage surge.
Cheers from Indonesia

[almalikmyalmalek]

my power suply i change capcitor now out put 8.4v why ?

[ΠάριςΑζής]

Unfortunately, my dear, this P.S.U will fail very soon again. But the reason is not that because it is cheap, but the way you think and choose to repair it. I do not intend to insult you, but you seem to ignore basic details of circuit analysis. You never analyse the failure in front of you. Common cause is the "cheapness" of the PSU. But this is not (always) the case. Therefore, if you keep performing repairs by replacing everything you find burned out by whatever else exists in your bench...you are opening love stories with the devil! Well, let me guess your next failure. This will be the bridge rectifier, along with the two switcing transistors. And here is the scenario of why this has high possibility to happen. You have replaced, this time, the NTC resistor, with a much smaller (ten times!) one. This means that the "new" replacement will not offer any comfort to the bridge rectifier from the huge inrush current. The bridge is therefore left alone to face it's fate! As for the new NTC, is as good as an ornament there. Offers nothing but it's beauty!
In the previous repair, you had replaced the two filter caps with much higher capacitances. Perhaps you thought that this was an upgrading, which in many cases is. But that alone, unfortunately, was a downgrading. And I explain why. When designing a product, many parameters should be taken into account. One of the most important here is the inrush current limitation. By putting bigger filtering caps, without increasing accordingly the current that the bridge can withstand, you are digging the grave of the bridge while it is still alive. And this is what you did. Now, you effectively have cancelled the function of the inrush current limiting, by putting almost a short circuit in its place. Well, the supposed delay time which the proper NTC would offer to the bridge, along with its smoothing function is gone. And when, angrily, you will open the poor little box again...the entire China would be to be blamed I suppose. My dear, "all you need" in order to perform successful repairs and have a peaceful mind during your life "is love"! Just follow the song of the good old Beatles! Next to it, treat the failed device as a human under medical operation with you as the surgery doctor. You will have amazing results! My 50 years experience of being involved in electronics' repairs can guarantee this to you...