Abhishek said:
Hi all,
I'm still using a computer that I assembled around 5 yrs back. It has a
1.4 GHz P4 processor and an Intel 850 GB board. The problem is that the
Power Supply stopped working a few days back. I went to hunt for it in
the hardware stores here and none of them have the obsolete power
supply anymore.
Somebody told me that I can use the same Power Supply Unit that is
being used in the contemporary systems.
The only problem is that the 850 GB board had to be supplied power
through 3 connectors(One for the board, one for the processor and one
which seems to be or the IDE controllers, pls correct me if I'm wrong).
The latest power supply units have only two power connectors for the
board, and the one for the IDE controllers seems to be missing.
Can I use a new power supply unit for my board?
Any help will be greatly appreciated as Intel has stopped supporting my
board.
Thanks,
Abhishek Srivastava
In the picture here, it looks like the board uses an ATX pre 2.0 supply.
Your motherboard has a 20 pin main power connector, a 2x2 ATX12V connector
for the processor, and other cables that power hard drives or CDROM etc.
http://prohardver.hu/html/lap/850gb/d850gb.png
Some of the ATX 2.0+ supplies have a 24 pin connector, and four of
the pins unsnap, so the supply will also work with a 20 pin motherboard.
It is also possible to plug a 24 pin connector into a 20 pin motherboard,
as long as there is room for the four extra pins to hang over one end.
That won't work in your case, since there are objects on either end of
the main power connector that would get in the way of the extra pins.
An ATX 2.0+ supply with detachable pins on the 24 pin connector, should
work OK, as the resulting 20 pin section will fit perfectly.
Here are some specs for ATX supplies. The first two specs are similar
to the supply you have currently. The third spec is what you are likely
to find in the shops.
http://web.archive.org/web/20030424...org/developer/specs/atx/ATX_ATX12V_PS_1_1.pdf
http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf
http://www.formfactors.org/developer\specs\ATX12V_PSDG_2_2_public_br2.pdf
First, compare page 27 of the first spec, to page 29 of the second spec.
The -5V signal on the connector was made optional at some point, and
there is not a lot of good reasons for a motherboard to need -5V.
Occasionally, there are motherboards that still draw a tiny amount
of current from that signal, and for those motherboards, a supply that
has no wire connected to pin 18 might be a problem. I hope this won't
be a problem for you.
Page 36 of the third spec shows a modern dual output supply. As long
as the four extra pins on the 24 pin connector can be unclipped, you
should be able to use one of those supplies. Note that, with the
use of SATA drives, there may be fewer connectors that you can use
with your ribbon cable based hard drives.
Your processor draws about 55 watts:
http://processorfinder.intel.com/details.aspx?sSpec=SL4WS
If using an ATX 2.0+ supply, the CPU current comes from 12V2.
The 55 watts of the processor is (55W/12V)*(1/0.90) = 5.09A
from 12V2. The 0.90 factor assumes the Vcore conversion on
the motherboard is 90% efficient. I expect a lot of ATX 2.0+
supplies will be able to manage the 5A loading.
I guess I could clarify the difference a bit. With a pre 2.0
supply, there was one output signal for +12V that drives all
the 12V wiring. Typically, I might recommend to a person they
get a 12V @ 15A rating (as printed on the label on the side
of the supply), as a good minimum for a P4 system. Your computer
uses 5A for the processor, and will use maybe 3-4 more amps
for hard drives, fans, CDROM etc. You can see that 15A should
be a reasonably generous spec for your system. (Maybe you'd find
that kind of support on a 300-350W supply. Check the label to be
sure.)
The ATX 2.0 supplies split the 12V output. They use one circuit
to power the processor via the 2x2 square connector. That is
12V2. They use 12V1 to power hard drives, the motherboard 12V wire,
and any other 12V loads. The label will list two ratings like
12V1 @ 8A and 12V2 @ 7A. The total is still 15A, but the current
is segregated to two output circuits. If using one of those
ATX 2.0 supplies (with the removable 4 pins on the 24 pin connector),
you'd be checking for a supply with at least 5A on 12V2, and
at least as many amps for 12V1 (to run hard drives). Many of
the true ATX 2.0+ supplies will supply more current than this,
so even if you blindly just buy one, I bet it will work.
So you can use a number of ATX power supplies to solve the problem.
If your board really needs the -5V on pin 18, that could be
a problem. But otherwise, if you get either an older 20 pin,
or a modern 24 pin (with removable 4 pin section), you should
be able to use your computer again.
Paul
