[Discuss-gnuradio] Re: Enclosure Fan connection

[Matt Ettus]

> Hello -- do you have any suggestions for wiring the enclosure fan with
> a "Gnuradio Rev 3" USRP board (s/n 356. 9/11/05).  Fan appears to be a
> 5v part - not clear from the pictures on the web where it's connected
> to.  Tap off the USB connector on the underside of the board?

The USRP boards shipping now have a fan connector.  For older boards
which don't, you'll need to do the following:

1 - cut off the fan connector
2 - solder the black wire to a ground point.  Suitable choices are the
ground connector on the lower left of the board, and the ground pin on
the power connector (the one on the side).
3 - solder the red wire to a power supply.   The best place to do this
is on the output pin of the power supply connector.

The fan is labeled 5V, but it is spec'ed from 4-7V, so it works fine on
the 6.3V which the above would get you.  It will be a little extra
noisy.  If that bothers you, you can put a 10 ohm resistor or a diode in
the power line to drop the speed.

Matt