Mike wrote:
> A new discovery, I shorted the green and black pins with a wire so I can
> turn on the PS outside of the case.
> I found out the new fans work outside of the case. So there must be
> something thats preventing the fans from working when everything is hooked
> up in the computer. Any ideas?

It still sounds like the power fed to the fans, is too low when the
power supply is cool. The old fans may work over a range of 5V to 12V,
for example. The new ones from 7V to 12V. It would be a matter of
shopping for a different fan, to get something that spins over the
same voltage range.

If the fan spins when outside the casing of the power supply, and
at that point in time, the power supply doesn't have any cooling as
a result, it means the inside of the power supply is getting hot,
so more voltage (closer to 12V) is being fed to the fan.

With your new fan, what you really want, is a voltage closer to 12V.
Instead of the sensor based voltage the fan is currently getting.

The objectives of this article, are a bit different than your project.
They evaluate fans here, for quietness. They reduce the voltage, as
part of getting to the quiet part. Note that some of the fans here,
start with a pretty low voltage. Just one, lists startup at 8.9V, which
is a bit on the high side. (Startup also means the ability to start
reliably every time. For example, if the room is ice cold, the fan
might not start at the same voltage, as when the room is at a normal
temp.)

http://www.silentpcreview.com/article63-page2.html

The other thing to note, is the original fan moved some number of
cubic feet per minute (CFM) of air. It has a performance spec. The
new fan should match that level of performance, so the power supply
gets at least the same level of cooling. Fans come in low, medium,
high, and ultra, which refers to both noise and CFM delivered. Even
if you were to find a fan that spins at the low voltage the power
supply is delivering, it might not be delivering the exact same
amount of air.

You can test and compare the fans, using your 9V battery, to get
some idea whether they're in the same "class" or not.

In the case of the one fan I replaced, the replacement delivers more
air than the original.

Paul

>
>
>
> "Mike" <nospam@email.com> wrote in message
> news:Faqwj.331$OB5.124@fe127.usenetserver.com...
>> I just checked the old and new fans with a 9 volt battery and they all
>> work. I put the old fans back in the PS and they worked. The circuit boards
>> on all 4 fans are encased in plastic so there in no way to get to them. I
>> am thinking the fans are proprietary to this PS. In order to replace the
>> fans the circuit boards have to be the same. The label on the PS says "with
>> Fan Sensor Control", whatever that means. The PS isnt an Antec or top of
>> the line but it does a great job. There is no way I can use the old fans,
>> way too noisy. There has to be a way to wire these new fans so they always
>> stay on when the computer is on
>>
>>
>
>