Power Issues

Hi All-

A relative asked me to look at his Dim 5100 that suddenly died. I
opened the power supply and see that the 6.3 Amp wired-in fuse is
blown. I could replace it rather easily, but I had a few questions:

1) Does the power supply fuse ever blow without some underlying fault
in the power supply itself and/or in the system ?

2) If I want to just replace the power supply, can I use any Mini-ATX
from Newegg? The present power supply says Shark ATX-400. Will any
400 watt ATX supply fit? Must it say "mini"? I am referring to
physical fit--will screws line up, etc?

As you can see I have no experience in purchasing power supplies.

Thanks for any suggestions!

Jim

Hi!

> A relative asked me to look at his Dim 5100 that suddenly died.

> 1) *Does the power supply fuse ever blow without some underlying
> fault in the power supply itself and/or in the system ?

It is extremely unlikely. Computer power supplies are designed to shut
down ("crowbar") their outputs in the face of a short or excessive
load. This is usually successful, self resetting (goes away when the
problem is fixed) and non-destructive. However, fuses get tired,
subjected to abuse, and only very rarely do they blow for no reason.

Look at the fuse--if it's glass bodied, is the glass discolored? If it
is darkened/discolored, the fuse blew due to a short. There's no point
in replacing it in that case--it will only blow again.

Power supplies are cheap enough and you probably want to replace it as
opposed to attempting a repair.

Computer power supplies are dangerous due to high voltage, high
frequency operating characteristics as well as charged capacitors.
They're safe enough if unplugged, but please put it back together
before you test it if you plan on replacing the fuse! (Oh, and don't
immediately hook it back up to the computer when/if you replace the
fuse. That's a good way to burn an otherwise good system that only
needed a power supply! Use a dummy load like an old hard drive and
short the green/black wires in the power connector to see what
happens.)

I believe you'll find the power supply is a standard BTX-type. Pick a
good quality supply, cheap ones can and do lie about their specs:
http://greyghost.mooo.com/psuthoughts/

One respected name brand to choose is PC Power and Cooling, if you
want one of the best supplies you can lay hands on. A 350-400 watt
supply should be more than enough for this system.

William

On Apr 14, 4:25*pm, "William R. Walsh" <wm_wa...@hotmail.com> wrote:
> Hi!
>
> > A relative asked me to look at his Dim 5100 that suddenly died.
> > 1) *Does the power supply fuse ever blow without some underlying
> > fault in the power supply itself and/or in the system ?
>
> It is extremely unlikely. Computer power supplies are designed to shut
> down ("crowbar") their outputs in the face of a short or excessive
> load. This is usually successful, self resetting (goes away when the
> problem is fixed) and non-destructive. However, fuses get tired,
> subjected to abuse, and only very rarely do they blow for no reason.
>
> Look at the fuse--if it's glass bodied, is the glass discolored? If it
> is darkened/discolored, the fuse blew due to a short. There's no point
> in replacing it in that case--it will only blow again.
>
> Power supplies are cheap enough and you probably want to replace it as
> opposed to attempting a repair.
>
> Computer power supplies are dangerous due to high voltage, high
> frequency operating characteristics as well as charged capacitors.
> They're safe enough if unplugged, but please put it back together
> before you test it if you plan on replacing the fuse! (Oh, and don't
> immediately hook it back up to the computer when/if you replace the
> fuse. That's a good way to burn an otherwise good system that only
> needed a power supply! Use a dummy load like an old hard drive and
> short the green/black wires in the power connector to see what
> happens.)
>
> I believe you'll find the power supply is a standard BTX-type. Pick a
> good quality supply, cheap ones can and do lie about their specs:http://greyghost.mooo.com/psuthoughts/
>
> One respected name brand to choose is PC Power and Cooling, if you
> want one of the best supplies you can lay hands on. A 350-400 watt
> supply should be more than enough for this system.
>
> William

Hey William-

Thanks for the info. I will not electrocute myself, but I am still a
bit unclear on the size power supply I need. The present one says
ATX-400, will at BTX fit in its place? The fuse is visibly
blackened so I guess it makes sense to replace the supply--just want
to get one that fits.

Thanks!
Jim

Hi!

> Thanks for the info. *I will not electrocute myself, *but I am
> still a bit unclear on the size power supply I need. The present
> one says ATX-400, *will at BTX fit in its place?

I should have realized that there is not an explicit "BTX" type
supply. An ATX power supply is what you'll need. Take the old one with
you for comparison purposes if you plan to buy one in a physical
store. If you plan to buy online, look for the following connectors:

24-pin ATX to motherboard
+12V (square, four pin) power to motherboard
4-pin Molex power connectors (most likely used for the CD/DVD drive)
SATA power connectors (for the hard disk)
Small four pin power plug for a floppy drive (if your system has one)

It's OK if the supply you buy has some extra connectors that you won't
be using. These can be set aside and safely ignored.

> The fuse is visibly blackened so I guess it makes sense to
> replace the supply--just want to get one that fits.

I think replacement is your best option. When these power supplies
fail, a lot of parts can go bad at once. Lack of any service
literature for them makes service harder, and they're not tolerant of
partial repairs--that is to say when you fix one problem, a remaining
problem may blow the good parts you just installed.

Good luck--this is a pretty easy fix. Just be sure you pick a power
supply from a reputable name so that it will meet the demands of the
system.

William

Hi!

> However I'd think they'd be charged to 12v so their damage
> would be limited to melting screwdrivers.

They'll discharge over time. The main set of capacitors to watch for
are the main filters. Those will store full AC line voltage, but they
do typically drain down within minutes of powering the supply off.

In any case, I keep a "handy widget" consisting of a resistor with
bent leads on the end of a long and heavy popsicle stick. I have
several for use with different capacitors both large and small. The
idea for doing this came from the sci.electronics.repair FAQ web site,
and it's a good one. Within a couple of seconds, these will discharge
almost any capacitor you come across.

William

Thanks to those who replied. I just ordered a Thermaltake power
supply and will give that a shot. Fuse is blackened and probably died
a traumatic death.

Jim Block

On Apr 15, 10:38�am, "Christopher Muto" <m...@worldnet.att.net> wrote:


> jim, if the system is still under warranty then you should call dell tech
> support and get a replacement power supply. �if it is no longer under
> warranty then you can call dell tech support and get the correct part number
> for a replacement and then call dell spare parts to buy one. �typically
> about $30 with 90 day warranty. �or, what is probably quicker is to just buy
> one from ebay - but shop carefully. �many sellers on ebay are selling low
> quality products that are 'for dell' but not actually dell branded. �i would
> prefer a used dell branded unit over some new piece of junk. �search by your
> computer model number or simply by "x8129' which is just one of the
> compatible part numbers. �you can also look for the dell part number (dpn)
> on the current power supply itself. �other than quality and fit (which is
> not too big of an issue), the other unknown issues with aftermarket power
> supplies is if it has sata style drive connectors which i believe you need,
> and if the cables are actually long enough to reach the drive bays. �so save
> yourself the headache and just get a genuine dell replacement part either
> new or used from dell or ebay. �good luck.
>
> "blockster" <JBloc...@aol.com> wrote in message
>
> news:5cfca997-f3d2-403d-8dec-...
>
>
>
> > Hi All-
>
> > A relative asked me to look at his Dim 5100 that suddenly died. �I
> > opened the power supply and see that the 6.3 Amp wired-in fuse is
> > blown. �I could replace it rather easily, but I had a few questions:
>
> > 1) �Does the power supply fuse ever blow without some underlying fault
> > in the power supply itself and/or in the system ?
>
> > 2) �If I want to just replace the power supply, can I use any Mini-ATX
> > from Newegg? �The present power supply says Shark ATX-400. �Will any
> > 400 watt ATX supply fit? �Must it say "mini"? �I am referring to
> > physical fit--will screws line up, etc?
>
> > As you can see I have no experience in purchasing power supplies.
>
> > Thanks for any suggestions!
>
> > Jim- Hide quoted text -
>
> - Show quoted text -