LPK12-450W safety capacitor shorted

[Taruga]

This power supply is from my nephew.
This power supply was short-circuited, as soon as he connected the power cord, the electrical panel of the house would shut down.
I tested it in my house and it seemed to work well, the electrical panel of the house did not turn off. The mismatches of 5VSB, +12, -12, +5 +3.3 were all normal. I was not sure what the problem was ... until I got an electric shock from touching the metal case of the power supply.

It seems that there was a current drain to the earth.

My house is older and there are no grounded electricity outlets, which is why the electrical panel was not going down in my house.

I opened the power supply and found that the Class-Y capacitors had a small burn mark.

These capacitors are designated 103Z 1KV.

I tested both, one of them seems to be fine although it has less capacitance compared to a new one. 5237pF instead of 8222pF





The other was detected as a 2788 Ω resistor instead of a capacitor in my tester.




I changed both.
This is a measurement of a new 103Z 1KV capacitor




The power supply is now working properly. There is no more current drain to the earth.

[sam_sam_sam]

Re: Enlight GPS-350CB-102 A

The component tester do you have a link to it

Nice repair

In the first photo it looks like it has a burnt spot on one side of it

[Taruga]

Re: Enlight GPS-350CB-102 A

The component tester do you have a link to it

Just look on ebay for:
LCR-T4 Mega328 Transistor Tester Diode Triode Capacitance ESR Meter

Example link:
https://www.ebay.com/itm/LCR-T4-Mega...sAAOSw~QNdCu2S

There are a wide variety of these testers

In the first photo it looks like it has a burnt spot on one side of it

Yeah, they both had burnt spots

[Taruga]

Re: Enlight GPS-350CB-102 A

I M P O R T A N T I N F O R M A T I O N


Ops... I was mistaken and I made confusion with the power supply, because I made the repair of two on the same day.
It was a LPK12-450W not sure what brand that had problems with the safety capacitors instead of the Enlight GPS-350CB-102 A


The problem I had with the Enlight GPS-350CB-102 A was another thing. The 5+5VSB was very high, instead of 5V, I had 7.6V and the power supply did not power on.

I replaced a 25V 47uF capacitor with high ESR ( 17Ω) on the primary side and now it powers up and all voltages are normal.

[Per Hansson]

Re: Enlight GPS-350CB-102 A

This is why both Y and X capacitors needs to be safety rated:
They are not allowed to have a failure mode that presents them as a short, only open...
A genuine Y capacitor will have a large number of agency approval stamps.

Here is an example: https://www.mouser.se/ProductDetail/...iAVrK%2Fj8A%3D

I changed the title of the thread to reflect the correct brand, do you also have a photo of the casing of the correct PSU?

[Taruga]

Re: LPK12-450W safety capacitor shorted

Thank you for changing the title of the thread. I wanted to, but I was unable.

I saw the link your posted with all the approval stamps, I didn't know that.
The one's I got to replace don't have any of that.

They look like this:


I will try to find and buy some with the approval stamps. Thanks for the info.

They are not full short, just one of them was detected as a 2788 Ω resistor instead of a capacitor.

Here's the photo of the power supply with the shorted safety capacitors:

[budm]

Re: LPK12-450W safety capacitor shorted

How is the cap connected in the circuit?
Those cap may be snubber cap not the safety cap.

[Taruga]

Re: LPK12-450W safety capacitor shorted

How is the cap connected in the circuit?
Those cap may be snubber cap not the safety cap.

I don't know what a snubber cap is, they're connected like this, live and neutral to the ground.

|

[budm]

Re: LPK12-450W safety capacitor shorted

OK, so they are supposed use the proper type of caps in that location but they did not.

[PeteS in CA]

Re: LPK12-450W safety capacitor shorted

The caps you replaced are .01uF, 1KVDC parts, not suited for used as Y Caps. For safety sake I strongly recommend/urge you to use safety agency rated Y caps. Further, I think .01uF Y caps would violate leakage current safety regulations. Probably the highest value you could use would be 4700pF.

Manufacturers of cheap junky power supplies often use generic DC caps instead of safety agency rated parts. I noticed that besides these unsafe cheap parts that the spaces where there should be common mode inductors there are jumper wires, another cheap-junk substitution.

[budm]

Re: LPK12-450W safety capacitor shorted

It is UNSAFE power supply, I would not eve try to use it any more. You already got a shock form it already. What else that they did not do properly to sell these unsafe power supplies to the public.

[Taruga]

Re: LPK12-450W safety capacitor shorted

The caps you replaced are .01uF, 1KVDC parts, not suited for used as Y Caps. For safety sake I strongly recommend/urge you to use safety agency rated Y caps.

Don't worry
My nephiew got new power supply, this one is/will not be used by him. It's for me, and when I need to use it, it will be mainly to test and repair noisy computer fans.
I have much better spare power supplies to put inside computers.

About the caps, those were what I had here to test and if it stopped leaking current to earth while I get the identical or better ones with the agency approval stamps and capacitance. But they don't look so easy to find at the places I usually buy caps.

The original reads around 5336pF and have no agency approval stamps.
This must have been a very cheap power supply.

The other power supply (FSP Raider 750W) I'm waiting for the 420v 390uF big cap, have Y Capacitors with agency approval stamps and they read about 470pF.

[Taruga]

Re: LPK12-450W safety capacitor shorted

It is UNSAFE power supply, I would not eve try to use it any more. You already got a shock form it already. What else that they did not do properly to sell these unsafe power supplies to the public.

What's unsafe, is my electricity outlets. I don't have grounded electricity outlets.
It's a 50 year old house. If I had grounded electricity outlets, then the electrical panel whould shut down and there would be no shock hazzard.

I started this post, because it was a curious issue of a power supply that didn't work on my nephiews house, but it worked fine on my house. Until, I noticed there was current flowing to the power supply metal case

[budm]

Re: LPK12-450W safety capacitor shorted

I am talking about the power supply, since they use the wrong part so what else did they did not do correctly to cut corner.
I would plug it into GFCI outlet to protect yourself, it is up to you.
You should check the leakage current one you finish with it to see how bad it is just to be sure.
They may also use the same wrong type of cap between the hot and the cold side also.

[RJARRRPCGP]

Re: LPK12-450W safety capacitor shorted

What's unsafe, is my electricity outlets. I don't have grounded electricity outlets.
It's a 50 year old house.

That reminds me of many old houses of the northeast U.S., with many older than 50 years old! Usually they are closer to 130 years old! But I lived in some until February 24, 2018 that had some properly grounded outlets, AFAIK. But a lot of them aren't!

[raider988]

Re: LPK12-450W safety capacitor shorted

I don't really understand how could it be legal to rent/sell house without outlets properly grounded.

[stj]

Re: LPK12-450W safety capacitor shorted

usa, a strange place.
there was a truck thread a while back,
in comifornia you have to get a yearly(?) inspection, you cant mess with the fuel/emission systems - not even a chrome airbox instead of the plastic one.
but the inspection does not examine brakes, tyres steering etc!!!!!!!

[RJARRRPCGP]

Re: LPK12-450W safety capacitor shorted

usa, a strange place.
there was a truck thread a while back,
in comifornia you have to get a yearly(?) inspection, you cant mess with the fuel/emission systems - not even a chrome airbox instead of the plastic one.
but the inspection does not examine brakes, tyres steering etc!!!!!!!

I bet in California, a lot of the houses aren't even that old, except for in a major part of San Francisco, of course. And some parts in Los Angeles.

The eastern U.S., has a lot of very old houses and the landlords often refuse to add a copper link for the ground. And of course, they often keep ancient outlets.
Yet, in organizational buildings and schools, people often have a bad habit of changing the fire alarm system just for the sake of change! I'm talking about apparatuses that can last for 40 years! But some get expelled in less than 20 years. Saw that some got expelled at no more than 16 years old or 17 years old! That's actually short for commercial-grade equipment! We're not talking about little stereotypical smoke alarms!

[stj]

Re: LPK12-450W safety capacitor shorted

i'v seen that,
it's often down to changing regulations and criminal installers who lie about it.

an example,
there was a recent change to the type of cabling you can use for emergency lighting/power.
(must be armored and fireproof)
the change only effects new installs, but some company's have been telling people the old stuff needs to be replaced!

[PeteS in CA]

Re: LPK12-450W safety capacitor shorted

My home town in California's Central Valley got a post office in 1861, and was incorporated in 1871. As a point of reference, California became a state in 1850. There is a section of the town with homes built in the late 19th century.

There are some homes and buildings around the state that date to Spanish colonial times and when California was a state in Mexico. Significant Spanish settlement didn't start until the 18th Century or so.