400w Power Supply on older 250w system?

  • Thread starter Thread starter Kevin G.
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K

Kevin G.

Hello all,

I have an older e-Machines system in which the Power Supply just died
out. The PS in this case is a 250w 20-Pin + 4 power supply. I do
happen to have a newer 400w 20-Pin + 4 power supply laying around here,
but I'm a bit unsure on whether to stick the larger wattage PS into
this machine.

Is there any harm in going larger with the wattage? My initial guess
would be no, because the machine is only going to use what voltage is
needed by the hardware (CPU, etc..). But before just sticking this
power supply into the machine I did want to get this question out
there, so I'm not looking for a motherboard replacement next :)

Any help on this would be appreciated.

KG
 
Kevin said:
I have an older e-Machines system in which the Power Supply just died
out. The PS in this case is a 250w 20-Pin + 4 power supply. I do
happen to have a newer 400w 20-Pin + 4 power supply laying around here,
but I'm a bit unsure on whether to stick the larger wattage PS into
this machine.

Is there any harm in going larger with the wattage?
Click to expand...

No.
 
Hello all,

I have an older e-Machines system in which the Power Supply just died
out. The PS in this case is a 250w 20-Pin + 4 power supply. I do
happen to have a newer 400w 20-Pin + 4 power supply laying around here,
but I'm a bit unsure on whether to stick the larger wattage PS into
this machine.
Click to expand...

Many eMachines use mATX PSU, and there are no true "400W"
mATX psu, they all realistically top out at 160-225W. I'm
just wondering if you were aware of this or if it would
potentially make the replacement incompatible. Since it was
rated for 250W, I'm suspecting it is a full PS2 sized ATX
but it was worth mentioning just in case...


Is there any harm in going larger with the wattage? My initial guess
would be no, because the machine is only going to use what voltage is
needed by the hardware (CPU, etc..). But before just sticking this
power supply into the machine I did want to get this question out
there, so I'm not looking for a motherboard replacement next :)

Any help on this would be appreciated.
Click to expand...


No the higher wattage alone isn't a problem. I presume it
is a decent name-brand, as some generics labeled as 400W
could be worse than the original 250W PSU was. So long as
your eMachine used that 4 pin plug on it's PSU (meaning it
used a significant amount of 12V power), it is expected a
newer supply is compatible enough. In some cases of using
older systems that drew mostly 5V power, and newer PSU
optimized for far lower 5V amperage and voltage monitoring
on the 12V line, the system can actually shut off from
detecting too high a 12V rail if not being instable or
failing to power on from insufficient 5V current. In the
case of an eMachine, I wouldn't expect it to draw too much
5V current but given some generic PSU are so overrated, it
wouldn't be surprising either to find a modern generic meant
for use in a system using mostly 12V current, didn't do well
on 5V rail.

When all else fails, the best strategy is to make sure it's
a reasonable quality PSU that you trust to shut down if the
voltages weren't in spec, and take readings with a
multimeter. Even so, this is mostly considering the odd
cases where there's a problem, which usually isn't the case
but if we ignore all the problem cases it does little good
for anyone that has a problem.
 
kony said:
Many eMachines use mATX PSU, and there are no true "400W"
mATX psu, they all realistically top out at 160-225W. I'm
just wondering if you were aware of this or if it would
potentially make the replacement incompatible. Since it was
rated for 250W, I'm suspecting it is a full PS2 sized ATX
but it was worth mentioning just in case...
Click to expand...


FWIW: I've repaired a few of those mATX machines and used a standard ATX
power supply and they worked fine.
The local computer store did have some of the mATX supplies...but they were
too expensive.

All I had to do was cut the mounting brackets off and use a nibbler to
slightly expand the opening in the rear
 
The 400 watt unit will work fine. The computer's components will only draw
as much power as they need.
 
Kevin said:
Hello all,

I have an older e-Machines system in which the Power Supply just died
out. The PS in this case is a 250w 20-Pin + 4 power supply. I do
happen to have a newer 400w 20-Pin + 4 power supply laying around here,
but I'm a bit unsure on whether to stick the larger wattage PS into
this machine.

Is there any harm in going larger with the wattage? My initial guess
would be no, because the machine is only going to use what voltage is
needed by the hardware (CPU, etc..). But before just sticking this
power supply into the machine I did want to get this question out
there, so I'm not looking for a motherboard replacement next :)

Any help on this would be appreciated.

KG
Click to expand...

If it's a black and silver emachine, don't bother. The board is already
cooked. When they die, they don't wake up. Speaking from the last half
dozen i've tried to revive.
 
Yep... it is the black/silver emachines, and sure enough it did turn
out to be a bad board.

Picked up a replacement Socket A board on Newegg for around $40, it
took the cpu and memory just fine, and even booted into XP without an
OS reinstall. A couple driver installs later, and the machine is
humming along perfectly. Normally I never like to install a piece of
hardware as big as a mobo without a clean OS install, but in this case
it seems to be rock solid without it - go figure :)
 
Yep... it is the black/silver emachines, and sure enough it did turn
out to be a bad board.

Picked up a replacement Socket A board on Newegg for around $40, it
took the cpu and memory just fine, and even booted into XP without an
OS reinstall. A couple driver installs later, and the machine is
humming along perfectly. Normally I never like to install a piece of
hardware as big as a mobo without a clean OS install, but in this case
it seems to be rock solid without it - go figure :)
Click to expand...


Much ado is made about running same OS install on a
different board, but often it's just a matter of one bad
experience making it seem more problematic than it really
is. Many people do so fine... if the system boots up the
first 3 times it's likely to be fine.
 
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