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If your real finicky you can file the
last few thousandths into the trace.
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Here you can see, sort of, that I've
filed about half way into the trace and the trace is visible on the
forward leading edge.
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I'm now ready to remove the outline
trace.
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The trace will pull off quite easily to
remove it.
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ditto
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The tools required to do the rest of the
job.
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Let's do the delicate part first...
I've used the needle nose pliers to
protect the glass shell of the magnetic reed switch as I make the first
90 degree bend.
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The reed switch is then placed in the
board and the needle nose pliers are used to hold and mark where the
second 90 degree bend is made.
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Here I've fully installed and soldered in
the reed switch for the power.
Remember to check to make sure you bend
them the right way. Without a magnet present the power switch
should have continuity between the two pins that have the traces running
to them, and no continuity for the back light reed switch.
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Flip it over and trim off the extra part
of the leads with right angle cutters.
Do the same for the back light reed
switch if you choose to use one.
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On the protective plastic sheeting cover
mark the displays with numbers which you'll remove when your done.
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Turn all the pots fully clockwise.
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Hook up + 9 Volts to pin 1 and ground to
pin 3. Attach a DVM across pins 8(+) and 10(-). Pin 1 is
denoted by the black triangle on the white label and the pins are
numbered consecutively around the display counter clockwise, while
looking at the back. So, in this picture pin 1 is in the upper
right, pin 6 lower right, pin 7 lower left, and pin 12 upper left.
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Read the millivolts across pins 8 and 10
and record the value.
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Now do the same for the other two
displays. After you've got all the values, go back and using the
trim pot on the back adjust the value across pins 8 and 10 to read the
lowest value you recorded.
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Mix up some two part epoxy
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Cover up the trim pot to seal and lock it
making sure the blob isn't to high that the display wont sit properly
when installed on the board.
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Ready to roll.
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Put the battery clips on the battery and
install it on the board, double check the polarity. I find it useful
to use a rubber band to hold it in place.
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Solder the battery clips in. The
polarity is correct .... right?
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Install the displays, lining up pin 1 on
the display with .......
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..............Pin 1 on the board.
Pin 1 on the board is the square through hole and is also marked with a
1.
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After you solder the displays in, trim
the excess leads with right angle cutters, you can do the excess battery
clip lead material while your at it.
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Next install the sensor
trim pots.
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Install the header connector, backlight
jumper or resistor, and the sensor load resistors if needed. Again
trim all the excess lead material from the back.
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D-Flux the back of the board to remove
all the solder flux, double check all your connections and solder joints
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So now we're ready to install the
battery, test the power and back light switch, make sure there's no
stray voltage between the sensor ground and the sensor positive
connections on the header connector and then hook up some sensors.
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I didn't include this in the above
description but I have started to use conformal coating on the boards
I've put together. It could aid the board and sensors if you
should flood your housing.
Special Note 02/2005: All
boards now come with Solder mask, which is the green coating you see on
standard industry PCB's. So if you want to use conformal coating
it only has to go over the the solder connections, not over the whole
trace runs.
As of late I haven't been using it and
assume I wont flood.
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Use it as you put the board
together making sure that everything that runs a signal is coated when
your done with the construction. I usually start construction by
coating the parts of the board I wont be able to reach after something
is installed, with out getting it into the through holes. The
displays are the trickiest part.
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