2 power supplies killed by lightning

[goodpsusearch]

The first psu is a variable voltage power supply (3V, 4.5V, 5V, 6V, 7.5V, 9V, 12V).

The bridge rectifier consisted of 4 smd 1A diodes "M7" and 2 of them failed shorted. Then, the 1A 250V fuse blew. I replaced the diodes and the fuse and the psu is now working. Photos attached:

[goodpsusearch]

Re: 2 power supplies killed by lightning

The second power supply is a noname 12V 1.0A unit.

Again, 2 of the 4x 1A diodes are shorted, the glass type fuse blew in a catastrophic way and a Y cap also blew. I already replaced the diodes and the fuse, but I need some input about the blue cap replacement.

Its values can be only partially read and I don't know what caps are considered to be compatible with the blown one. I attach a photo of the cap. Any help would be welcome

[goontron]

Re: 2 power supplies killed by lightning

looks like the cap wasnt even safety rated..... when you replace it make sure the new one is.

[eccerr0r]

Re: 2 power supplies killed by lightning

Chances are, the cap had "222 1KV" printed on it, a 0.0022 microfarad capacitor. The other possible values are not common and therefore more expensive (which this can't be). But yes, make sure it's Y-rated, you don't want it to fail as a short (is it shorted now? If it is, that's what you DON'T want happen...)

[goodpsusearch]

Re: 2 power supplies killed by lightning

I thought that the color stated if the cap was Y-rated or just ceramic.
Blue color = Y cap
Any other color= ceramic cap
Was I wrong?

Edit: It failed open.

[budm]

Re: 2 power supplies killed by lightning

It can be any color, it should have X/Y printed on the body. That cap is used to reduce the noise to pass FCC test. The value will be every low since you do want too much AC leakage current, .001~.0047 will be fine, the unit will still function without this cap.
For example:
http://www.mouser.com/ProductDetail/...y0Q2bAiJDDg%3d

[PeteS in CA]

Re: 2 power supplies killed by lightning

Cera-Mite Y caps (and X caps, too) are or have been orange. Color means approximately nothing. Look for the "X" or "Y", and for the safety agency marks. Like eccrrOr said, that blown cap was 2200pF, probable 1KV (you can see the second capacitance digit and the multiplier digit, and you can see the "KV" from the voltage rating). Definitely get a real Y cap!

[goodpsusearch]

Re: 2 power supplies killed by lightning

I fixed it!

I used a cap from a dead computer power supply, the cap was on the same position, across the main transformer.

Thank you for your help!

[Kiriakos GR]

Re: 2 power supplies killed by lightning

I used to bring in life many fax machine which was failing apart due HV voltage in the telephone lines due lightning (collected by the telephony pols).

Yes Mains voltage is just one of the doors which the lightning can enter in your home.
The other is the telephone line.

[momaka]

Re: 2 power supplies killed by lightning

Now that is a proper Y-rated safety cap!

The adjustable power adapter looks nice. Can be pretty handy for testing breadboard projects that may require some odd voltage.