A7V8X Problem

[doug]

I installed a chassis fan with the plug-in to the Power Supply and a tach
signal plug-in to the mobo. It tested alright with the cover off so I shut
it down, put the cover back on, vacuumed the CPU and started it up. Well, I
got the reiterative mumbling out of the speaker that probably says your mobo
isn't doing too well. I haven't been able to boot up. Can anyone explain
what is going on? I hope the mobo is still good.

Thx, Doug Eilertson

 

[Ed]

I installed a chassis fan with the plug-in to the Power Supply and a tach
signal plug-in to the mobo. It tested alright with the cover off so I shut
it down, put the cover back on, vacuumed the CPU and started it up. Well, I
got the reiterative mumbling out of the speaker that probably says your mobo
isn't doing too well. I haven't been able to boot up. Can anyone explain
what is going on? I hope the mobo is still good.

Thx, Doug Eilertson

You sure you didn't suck up a jumper or something, forget to plug
something back in? ;P
I read in these groups some time ago that home type vacuum cleaners can
produce strong static charges and damage boards. I've been using a
Dry/Wet Shop-Vac type without any problems for years so I don't really
know how true that is.

Ed

 

[doug]

I used it before. I only point it to the heat sink to suck up the
accumulated dust on the heat sink. I will check for jumpers though - good
idea. The vac helps cool the cpu down. The temp has always been kind of
high and with a fan that exhausts more cfm than what the cpu fan is putting
out should keep it cooler. It looks like I will be search for another mb
soon if the problem isn't resolved.

 

[Paul]

I used it before. I only point it to the heat sink to suck up the
accumulated dust on the heat sink. I will check for jumpers though - good
idea. The vac helps cool the cpu down. The temp has always been kind of
high and with a fan that exhausts more cfm than what the cpu fan is putting
out should keep it cooler. It looks like I will be search for another mb
soon if the problem isn't resolved.

Can you get the computer to boot, with the new fan disconnected
from the motherboard ? If you can, try entering the BIOS and
go to the Power Monitor. For the fan monitoring, set them all
to <Disable>, so the BIOS no longer checks fan speed. Then
see if the computer will boot with your new fan connection.
If it does, enter the BIOS and go to the Power Monitor again
and see what RPM the fan is at. If the RPMs are low, they may
be below the acceptable threshold defined in the BIOS, in which
case it may read the RPMs as zero, or some low number. Using
the <Ignore> setting on that one fan should help.

If your power supply has both a specialized "fan only" power plug
and the ordinary drive power plugs, try plugging the fan into
a drive connector instead. The fan will run at full speed, and
there is no chance that the ground on the fan is being screwed
up by the "fan only" plug. There are many ways for a "fan only"
plug controller to be designed, and if it is using an open
collector low-side voltage control, it could be lifting ground
on the fan above the normal ground level, which will screw up
the tach signal when it is connected to the motherboard. A way
to check, would be to take a voltmeter, and measure from the
red wire on the fan, to chassis, and then make a second measurement
from the black wire on the fan to the chassis. The black wire
should be at the same potential as ground, so the voltmeter
should read zero between black fan-only ground and the chassis
of the computer.

If you want speed control, it might be better to use a drive
power connector, and a product like a FanMate to reduce the
voltage to the fan. The fan-only power on a power supply, won't
crank up the fan speed, until the computer is quite hot (that
is, assuming it is actually a controller and not just a static
voltage source).

HTH,
Paul