I have got a 5 volt fan on a video board, an ATI Radeon 64 ddr VIVO (yes,
old, but used for video recording not games). All this time the fan has
been
running after windows shuts down. I just realized it as the fan is starting
to wear out and is making a noise to where I thought some critter got caught
in the case and was trying to get out.

I unplugged the fan from the video board connector and plugged it into the
5v part of a regular power supply connector. Same problem, when windows
shuts down, the fan slows down, but still keeps spinning away, although at
low speed. I plugged it into the 12 volt connector and it spun like crazy
when it was powered up but it did shut down when windows shut down.

I can solve the problem by putting one of those variable speed fan
potentiometers to drop the 12 down to 5. I got one left over from
a cpu fan that needed to spin at high speed all the time. I assume
that will fix the problem no?

Anyway, I put the video board in another computer, different power
supply and different mombo and it worked fine. Was wondering if
this is a power supply problem or the motherboard? Could some ACPI
setting in cmos cause this problem? There is something in the bios about
5v and s3 settings for resume and suspend but they are cryptic. If there
was a "wake-up on someone looking at the screen" then I could see
keeping the fan running on the video board.


--
================================================== =====================
Beemer Biker joestateson (AT) grandecom (DOT) net
http://ResearchRiders.org Ask about my 99'R1100RT
http://TipsForTheComputingImpaired.com
================================================== =====================

Previously Beemer Biker <joestateson (AT) grandecom (DOT) net> wrote:
The basic problem is that your PSU seems not to shut down fully.
Since you say the the voltage on 5V line drops, but does not go
away completely, you seem to have a shot PSU, since that voltage
has no correct values except 5V and 0V.

An other possibility is that there is a short between the standby
power (5Vsb) and the 5V line, and the standby line can just barely
generate some voltage when main bpower goes away, enough to keep the
fan spinning. Such a short could be in the PSU or on the mainboard.
It could even be a PS/2 or USB power jumper set wrongly. Many
mainboards have jumpers where you can power keyboard/Mouse/USB from
the standby voltage instead of 5V, so you can start your computer from
keyboard or mouse. The jumpers I have seen did not allow you to short
out 5V and 5Vsb with normal jumpers, but such a design is certainly
possible.

You should not contiune to operate your computer like this.
Something is seriously wrong.

Arno

"Arno Wagner" <me (AT) privacy (DOT) net> wrote

SNIP

Thanks Arno....

I downloaded the manual from msi for my K7D master and did not see any
jumpers for USB power. I have seen those on other motherboards though. I
may pull the motherboard out and see if I can spot something.

I swapped the power supply from Macron MPT-400 to a Powmax-450 and things
got worse. It will not power on unless I hold in the front power "on
switch" while switching on the rear power supply. I discovered this by
accident when holding down the front switch thinking I needed to reset the
power supply.

If I turn on the rear switch, nothing happens....ie: the little green led on
the motherboard does not light up. If I then press the front panel on/off
switch, the little green led lights up. The system never turns on, no
matter how long I hold in the front panel switch nor how many time I push it
in and out. Strangely, if I turn off and on the power supply while holding
the front switch in, the system power up. It does this with no load other
than the two cpu's and their fans. The Macron was dated 9/2001 and is ATX
12V (verion 1.2??) but there was no date on the Powmax. It is an LP6100
and I think I got it in 2003 from a liquidator (computer geeks). Both of
those power supplies google and I dont really see any complaints. They are
both AMD rated. I think the problem is the motherboard and I will put the
old power supply back in, at least the on/off switch worked with it.


--
================================================== =====================
Beemer Biker joestateson (AT) grandecom (DOT) net
http://ResearchRiders.org Ask about my 99'R1100RT
http://TipsForTheComputingImpaired.com
================================================== =====================

Previously Beemer Biker <joestateson (AT) grandecom (DOT) net> wrote:

I think this is further evidence of a short: The second PSU may depend
on 5Vsb for its power on circuit more than the forst one, or it may
just have less power output on 5Vsb. You should definitely go back to
the first PSU, if you must operate the computer. The second PSU may
get irreversible damaged by this short. (The first one may too, but
it has survived for quite some time, so there is hope...).

Dismantling the board is a good idea. Some metal parts may cause the
short.

Here is a connector schematic:

http://xtronics.com/reference/atx_pinout.htm

+%V is all the red wires (reliabley), +5Vsb is pin 9 and
often violet. If you have access to meauring equipment,
you can test whether pin 9 and the red ones are connected.
They should be isolated from each others (> 1000 Ohm or so).

Arno