Paul R. Hunt said:
Sorry for OT post.
Tried Promise techs but have been ignored so far...
The Ultra133 tx2 has a four pin header for IDE activity.
My HD activity LED has two leads. Which pins should be used on the
Promise board?
Thanks. Paul H.
I have an Ultra100 tx2 with the four pin header.
If you look at the card and the little copper tracks, you
may see something like this -
--X +
/
/ X -
| |
\ X -
\
--X +
The outside two pins appear to be wired together, and they
run to a current limiting resistor. The inside two pins
are wired together, and I think they run off to the driver.
I have a home brewed LED and cable assembly, and my red (+)
wire is currently connected to the top pin, while my black (-)
wire goes to the third pin down from the top, as I needed some
room to be able to see the pins while inserting the wire. I
used crimp pins that are designed to fit over the square posts
of the header, and put shrink wrap around them, to insulate and
prevent them from touching adjacent pins.
If your LED has a two pin connector, then use the top two pins.
If your LED has a three pin connector, and the center wire is
missing, then you can still plug it into the top pin. If the LED
had a four pin header, and used the outer two pins for the
connections, then that wouldn't work, and you would need to
extract a pin from the LED cable assembly and move it to
a different hole in the plastic shroud, such that the wires
lined up with a (+) and a (-).
If the LED doesn't light the first time you connect everything
up, simply disconnect the cable and rotate the connector 180
degrees. Since 5V drive is used, the LED won't be damaged (most
$0.10 LEDs have a 5V reverse rating). In fact, if you want, you
can even plug this in while everything is powered, as long as
you aren't so clumsy as to bend the pins enough to short them
to something else. The LED pins can be safely shorted to one
another, due to the use of the current limiting resistor, so it
is pretty hard to damage the circuit. Of course, use ESD
precautions, draining any static off your fingers, before
working on it. (My standard recommendation is to power down and
unplug the power supply, before working in any computer, because
accidents do happen, and if you drop tools, or wires into a
working computer, sparks can fly. The high current capability
of the ATX PS means whatever short develops, something will
be melted and/or will burn. I've had one nasty accident working
in a live chassis, but that is a story for another day...)
HTH,
Paul
