Woops PSU Blown A7N8XD & Enermax PSU

  • Thread starter Thread starter Bill H
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Bill H

Hello;

ASUS A7N8X Deluxe and Enermax 350W PSU.

The missus switched on the PC and said that it immediately immited a loud
bang.

I checked it out and when the UPS is switched on it fails.

Removed the UPS and connected straight into the PSU with a new connector,
another bang!!

Removed the PSU and took it apart no obvious burnt out components, change
the fuse in the power connector and switched back on..........fireworks came
early this year!!!

I tried out a spare PSU that I had in the garage but the system case would
not power up dead as a Dodo, problem is not sure the PSU was working anyway?
Tried to test the PSU on its own from info off the web (Connect the green
wire to any common and switch on) Nothing happened, so PSU might be duff.

Well I now have a dilema, I know I need a PSU so I'll have to get one but
what are the chances of the Mobo being fried??
Tried an Ohm test on the power connectors on the HD's and CDRom and no
obvious shorts but how can I test the Mobo (Again no obvious damage)

If the Mobo is damaged what are the chances of a damage Mobo blowing a new
PSU??

Last note when I took the Enermax apart the internal fuse was intact?

Any help would be great. Need a PSU in a hurry only shop open tommorow is PC
World and think they only sell JeanTech.

Regards

Skavenger
 
Bill said:
Well I now have a dilema, I know I need a PSU so I'll have to get one but
what are the chances of the Mobo being fried??
Click to expand...

Difficult to say, about the only thing you can do is try a known good PSU.
Tried an Ohm test on the power connectors on the HD's and CDRom and no
obvious shorts but how can I test the Mobo (Again no obvious damage)
Click to expand...

Can try that, that's not likely to tell if it will actually work though.
If the Mobo is damaged what are the chances of a damage Mobo blowing a new
PSU??
Click to expand...

Unlikely, unless the PSU is so badly designed it should be thrown in the
trash. If it's shorted it should just not power up.
Last note when I took the Enermax apart the internal fuse was intact?
Click to expand...

Possible things can blow without taking out the fuse..
 
"Bill H" said:
Hello;

ASUS A7N8X Deluxe and Enermax 350W PSU.

The missus switched on the PC and said that it immediately immited a loud
bang.

I checked it out and when the UPS is switched on it fails.

Removed the UPS and connected straight into the PSU with a new connector,
another bang!!

Removed the PSU and took it apart no obvious burnt out components, change
the fuse in the power connector and switched back on..........fireworks came
early this year!!!

I tried out a spare PSU that I had in the garage but the system case would
not power up dead as a Dodo, problem is not sure the PSU was working anyway?
Tried to test the PSU on its own from info off the web (Connect the green
wire to any common and switch on) Nothing happened, so PSU might be duff.

Well I now have a dilema, I know I need a PSU so I'll have to get one but
what are the chances of the Mobo being fried??
Tried an Ohm test on the power connectors on the HD's and CDRom and no
obvious shorts but how can I test the Mobo (Again no obvious damage)

If the Mobo is damaged what are the chances of a damage Mobo blowing a new
PSU??

Last note when I took the Enermax apart the internal fuse was intact?

Any help would be great. Need a PSU in a hurry only shop open tommorow is PC
World and think they only sell JeanTech.

Regards

Skavenger
Click to expand...

There is a big difference between "no obvious shorts" and "it works".
Testing for shorts on the motherboard doesn't tell you whether it
will work when powered the next time or not. Internal damage to
silicon, does not mean you can necessarily see the effect externally,
as measured by an ohmmeter.

To test the motherboard, measure from +3.3V to COM, from +5V to COM,
from +12V to COM, from +3.3V to +5V, and so on. In other words, test
for rail to rail shorts, test for rail to ground shorts. There are
multiple +3.3V and +5V wires, but you don't need to test all
combinations of the wires, just obvious combinations of +3.3V, +5V,
+12V, -5V, -12V, +5VSB, and COM. Since there could be filter capacitors
on some of those rails, some of them could give a steadily increasing
reading, which is fine.

When a PSU makes a loud "bang" sound, that is the last time you
plug it to a motherboard! Even if you were to send it to a shop
and have it repaired (which would not be cost effective), I would
never trust $1000 worth of electronics to a suspect $39 box full of
destructive power.

The purpose of an internal fuse inside a power supply, is mainly
to protect the wiring in your house. The fuse cannot possibly work
fast enough, to prevent damage to the load side of the PSU. It is
more of a fire prevention feature than anything else.

Your A7N8X draws most current from the +5V rail. Depending on whether
you have a high power video card or not, I would want a new power
supply with 5V @ 20A rating (for a video card that doesn't use a
disk drive power connector) to 5V @ 25A (for a video card that does
use a disk drive power connector for extra power). The other rails
are not as critical. This is different advice than I would give for
the current generation of motherboards, where the majority of power
comes from +12V (in which case 12V @ 15A would be a bare minimum, and
certainly a bit more than that would not hurt).

Check the label on the side of the Jeantech, to see if it at least
meets the +5V requirement of your current motherboard, but also
make sure it has a good +12V rating, if you plan to use it for a
future motherboard.

Paul
 
Thanks for all the help,
As I needed to fix it today after carrying out some more tests, Ohm Test on
Mobo Power Socket, I popped down to PC World this morning (Only place open
on a Sunday).

PC World only sell Jantech and one Hipper (£69.99) I had already checked the
specs on the Net, needed a 450W to be sure but low and behold they only had
the Jeantech 400W (£39.99) & 600W (£69.99).
After a bit of a discussion with the promise of it it don't work or blows up
cos you have a faulty Mobo bring it back and we'll refund you I took it the
Jeantech 400W JNP-400P.

The power rating seemed OK, but having two +12v ratings confused me
slightly.

+5V 35A
+3.3V 28A
+12V1 15A
+12V2 17A

What are the two +12V.

Took it home connected it all up and voila my Neon Fan kicked in and the
machine started up and is working fine, tested it running Unreal Tournement
and all seemed OK.
Two zaps with a busted PSU and the Mobo survived.......phew
The Jeantech might not be the best but at least it works!! pretty quite too.

Many thanks

Bill H
 
Skavenger said:
Thanks for all the help,
As I needed to fix it today after carrying out some more tests, Ohm Test on
Mobo Power Socket, I popped down to PC World this morning (Only place open
on a Sunday).

PC World only sell Jantech and one Hipper (£69.99) I had already checked the
specs on the Net, needed a 450W to be sure but low and behold they only had
the Jeantech 400W (£39.99) & 600W (£69.99).
After a bit of a discussion with the promise of it it don't work or blows up
cos you have a faulty Mobo bring it back and we'll refund you I took it the
Jeantech 400W JNP-400P.

The power rating seemed OK, but having two +12v ratings confused me
slightly.

+5V 35A
+3.3V 28A
+12V1 15A
+12V2 17A

What are the two +12V.

Took it home connected it all up and voila my Neon Fan kicked in and the
machine started up and is working fine, tested it running Unreal Tournement
and all seemed OK.
Two zaps with a busted PSU and the Mobo survived.......phew
The Jeantech might not be the best but at least it works!! pretty quite too.

Many thanks

Bill H
Click to expand...

The latest standard for ATX power supplies, splits the 12V into
two separate circuits. The ATX 12V 2x2 connector, which powers
the processor, has its own 12V feed. The rest of the 12V loading,
which would be fans, disk drives, aux video card feed and so on,
is powered by the other 12V circuit.

In any case, the 5V 35A rating is good for your current board, so
there should not be a problem.

Paul
 
Cheers for all the info

Ta
Paul said:
The latest standard for ATX power supplies, splits the 12V into
two separate circuits. The ATX 12V 2x2 connector, which powers
the processor, has its own 12V feed. The rest of the 12V loading,
which would be fans, disk drives, aux video card feed and so on,
is powered by the other 12V circuit.

In any case, the 5V 35A rating is good for your current board, so
there should not be a problem.

Paul
Click to expand...
 
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