Well, I am tiring to visualize the flow. But am having a hard time doing
it. But let me give you one rule of thumb. The cooler a CPU can run, the
more efficient it will work. The same with the whole computer. The CPU
should have a fan on it. This will keep the CPU cooled down. Now, it kinda
sounds like the fan from the PSU also was the fan that cooled the CPU (on
the old unit). Now the fan is no longer cooling the CPU. So, go to Radio
Shack, or your local computer store, and get a CPU fan. It fits on the heat
sink, and 2-4 screws will screw into, between the heat sink vents. If you
are getting two fans running opposite of each other, (I.E.back forcing out,
and the front fan forcing out, creating a void inside the case), you will
need to reverse one of the two fans. You need to create a nice airflow
through the case (I.E. Front to rear, or Rear to Front.) If you only have
one fan, may I suggest another, to create a nice airflow...

Hope this helps.
Rick

"Caroline" wrote in message
k.net...
I replaced my computer's 90-watt Newton power supply with a 180-watt
Fortron
power supply today. I have not added any other new components, so the
total
power consumed should not have changed. The new power supply unit (PSU)
fits
perfectly in every way except one: The air flow direction is reversed. The
old
fan's intake was on the back of the computer case. The fan exhaust was
into the
computer, across the heat sink and CPU, and out the back of the case. The
old
way arguably caused the case to be under a slight pressure.

The new fan arguably puts the case under a slight vacuum.

The heat sink prongs are hot but not so hot I can't safely (no burns)
leave a
finger on it.

Should I just observe for awhile, playing it by ear?

Or should I figure out a way to reverse the fan flow direction in the new
power
supply?

All experience is welcome. I googled and am not finding anything
definitive.

Aside: After a lot of research on physical fit and electrical fit, brand
names,
and cost, I bought the new power supply from newegg.com. With shipping,
altogether it cost $26. Ordered Tuesday night late, arrived Friday
afternoon.