PSU Voltages???

[grss1982]

My first post.

Sorry for being a noob.

But I wanted to ask if the PSU Voltages of 3.7v and 12.5V on the respective rails are safe. Or are these voltages dangerous to a mobo.

I was under the notion that PSU general provide 12v and 3.3v on the respective rails, right?

I've opened the PSU up for a visual inspection and there seems to be no bulging capacitors. I'll take pictures and post them later on though. [ Don't have a camera just a built-in camera on a phone :-( ]

BTW, I measured them with a digital multi-meter.

PSU model is:

JPSW-4 300W

Its apparently made in Thailand.


Any and all replies apreciated. Thanks!!!

[Galvanized]

Re: PSU Voltages???

All the ATX specs and revisions can be found at http://www.formfactors.org/
Many usefull PSU info links can be found at http://www.jonnyguru.com/links.php

On the PSU's sticker minumum load per rail should be indicated. This load should be present before voltage readings are true via DMM (digital multimeter). If the PSU's voltages are checked with the comp up and running, this is good enough.

ATX states that all rails should be + or - 5%, with the -12V rail being permitted + or - 10%.

So, 3.3 x 1.05 = 3.465, looks like 3.7V is very high. It might get this high if the unit was tested without a load but I doubt it.

12 x 1.05 = 12.6, so the 12.5V is high but within spec.

List the capacitor brands in the PSU. Sometimes caps can go bad without visual signs.

High voltages are not good for the MB. 3.3V serves the RAM.

Forgot: Welcome to Badcaps.

[grss1982]

Re: PSU Voltages???

@Galvanized: Thanks for the reply and the WELCOME as well. :-)

Anyways went ahead and took of the cover of this baby:

And from what I can see:

2xBig Capacitors: Canicon 220uF, 200V, 85 C

there's also a Canicon 2.2uF, 50v, 105 C

There are others as well but i'm having a hard time idenbtifying them because the wires are in the way. :-(

[gdement]

Re: PSU Voltages???

The large input caps normally are pretty reliable on most PSU's, but I wouldn't put anything past Canicon. I'm not sure I've ever seen a Canicon that wasn't bad.

Even so, the caps you really have to worry about are the mid size caps on the output side. But I'm not sure if bad caps could cause your voltage to be high - I'd expect that to cause voltages to go low instead.

[grss1982]

Re: PSU Voltages???

Some images: :-)

[kc8adu]

Re: PSU Voltages???

gutless wonder.
you have a fine rifle target.

[grss1982]

Re: PSU Voltages???

gutless wonder.
you have a fine rifle target.

Yeah wished I had an Armalite. :-)

Incidentally after I took this pics the POS would'nt power up anymore.

DAMN PSU

[Galvanized]

Re: PSU Voltages???

If you warmed the caps up with a hair dryer, it *might* power up.
That would indicate that the caps had dried out.