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FM-100 Page 20
towards U3 before soldering all 18 pins.
11A. Install D2, one of the small red LEDs. You will notice that if you look
straight at the LED there is a flat side. This indicates the Cathode side of
the LED. The Cathode side is also indicated by the shorter of the two leads.
Make sure to install the flat side or the shorter lead in the same way as
shown in your diagram. They only light up if they are installed correctly.
Before soldering though, this and the next LED are the only parts that we
do not mound flush to the PC board. In this case we want to mount them so
the lens of the LED is at the same height as DS1 and DS2. These LEDs will
eventually be lining up with holes in the front panel. Once the height is set,
bend the leads to hold the LED in place, then solder.
12A. Install D3 in the same fashion, making sure it is at the same height
and orientation as in the previous step.
Now would be a good time to check all of your solder connections for opens
and solder bridges on the back side of the board. Now we are moving on to
install jumper connections and a capacitor on the back side of the board. The
parts on the back side of the board are marked in gray instead of black.
13A. Install J3, a five pin jumper block, short leads go into the board. Again
make sure you are putting them in the opposite side of the board from
where the rest of the parts are located. This jack is where the numeric
display gets its power and the data for display values.
14A. Install J7, another five pin jumper block. This is where the power for
the bargraphs is applied and the signal levels for the bargraphs are sent.
15A. Install C78, a 10uF electrolytic capacitor. Notice this is the first
capacitor of this type. You want to be sure that you pay close attention to
the polarity markings on this part. In most cases the negative (-) side is
marked on the capacitor, while the positive side (+) is marked on the parts
layout. If you fail to mount this component correctly, the part can fail as well
as prevent proper operation of your project. We will be installing many more
of these later in the project so be sure and remember this!
Cool! We have just completed the display board and we are almost ready to
move on. First we want to check our display board to make sure there are no
solder bridges or cold solder joints. Next check orientation of your parts for
correct installation.
A
K
1/4"
Same height
as DS1+DS2