Pin 12 and Pin 9 in ATX Power connector - wattage question

[BobTheCat]

We tested my PS connector because the mobo and cpu stopped working.

Pin 12 is supposed to be at -12 watts but is putting out onlt -11 watts.

Pin 9 is supposed to put out +5 watts but is outputting +7.5 watts.

(The rest are what they should be).

Do we need a new PS or are these variations normal and OK?

[We MAY have gotten a lightning jolt, not sure; no burning smell).

Thanks!
Bob

 

[CBFalconer]

We tested my PS connector because the mobo and cpu stopped working.

Pin 12 is supposed to be at -12 watts but is putting out onlt -11 watts.

Pin 9 is supposed to put out +5 watts but is outputting +7.5 watts.

(The rest are what they should be).

Do we need a new PS or are these variations normal and OK?

[We MAY have gotten a lightning jolt, not sure; no burning smell).

Those are volts, not watts. The 7.5 number is scary, and may have
taken out your MB, CPU, and peripheral cards. The PS is junk.

 

[Ralph Wade Phillips]

Howdy!

We tested my PS connector because the mobo and cpu stopped working.

Did you do this with a load on? Or did you unplug the PSU and test
it unloaded?

Pin 12 is supposed to be at -12 watts but is putting out onlt -11 watts.

Watts? Don't you mean "volts"?

Pin 9 is supposed to put out +5 watts but is outputting +7.5 watts.

Same thing - don't you mean volts?

(The rest are what they should be).

Do we need a new PS or are these variations normal and OK?

Depends. Was the PSU loaded to at least 10% of max? If not, then
it could be simply that the regulation was fubared due to not enough load.

If, however, you were prodding the back of the connector with the
power on - yah, I'd say you're fubared on the power supply. Get a new one.

[We MAY have gotten a lightning jolt, not sure; no burning smell).

Heh. If it had been THAT bad (burning smell), you'd not have any
voltage out at all ...

RwP

 

[kony]

We tested my PS connector because the mobo and cpu stopped working.

Pin 12 is supposed to be at -12 watts but is putting out onlt -11 watts.

You mean volts, and it doesn't matter because boards don't
use -12V very often.

Pin 9 is supposed to put out +5 watts but is outputting +7.5 watts.

Pin 9 should be 5VSB, 5 volts. I have to wonder though if
you're taking the readings correctly since you used the term
watts instead of volts. If you had measured between that
pin and a 12V line instead of a ground, it would be
conceivable that you'd end up with a 7.5V reading.
Here's a handy aid,
http://69.36.189.159/usr_1034/atx_on.gif

Are you sure you measured between 5VSB and a ground (COM) ?
If so, yes your PSU is malfunctioning.

What make and model PSU is it? What are the amperage (A)
ratings on the sticker for 3V, 5V, 12V, and 5VSB (sometimes
called 5VFP) ?

Plus, please describe the major components in the system so
we have a baseline for the expected power consumption of the
system, including any devices connected to PS/2 or USB, and
whether your motherboard has the PS/2 and/or USB power
jumper set to use 5V or 5VSB (see motherboard manual for the
jumper(s) location(s).

(The rest are what they should be).

Do we need a new PS or are these variations normal and OK?

If your reading is correct you need another PSU, but I
recommend rechecking it again.

[We MAY have gotten a lightning jolt, not sure; no burning smell).

You can also unplug the PSU from everything, THEN reconnect
the AC cord and measure that 5VSB- unlike the powered-on
state for the other power rails (voltages) the 5VSB should
be nearer 5.0V even with nothing connected.

You might try unplugging the PSU from AC for a few minutes
if you hadn't already. If that doesn't help, try clearing
the motherboard CMOS via jumper or pulling the battery for
10 minutes (again while the AC cord is unplugged or PSU is
switched off by a power switch on it's rear).