QCX assembly Rev 1.08
15
It is normal to need to slightly squeeze the rows of pins inwards to fit in the holes on the PCB. IC
manufacturers always supply leaded (through-hole) ICs with the pins a little too wide-spaced.
As before, I find it useful to solder initially two pins at diagonal opposites of the chip, then check
that the chip is nicely seated evenly on the board, before soldering the other pins.
3.4
Install all 100nF (0.1uF
, “104”) capacitors
There are 16 100nF (0.1uF) capacitors, these have the code “104” written on them. Be sure to
identify the correct capacitors, using a magnifying glass or jeweller’s loupe. These capacitors are
C2, C3, C6, C12, C29, C32, C34, C35, C36, C39, C40, C41, C48, C49, C50 and C52. Place each
in the correct position on the board, and slightly bend the legs outwards at about 30-degrees angle
so that they stay in place. Then solder the wires, and trim the excess wire length with wire cutters.
It does not matter which way round the capacitors are installed. However, it is very good practice
to install them all with the capacitor label facing in the same direction. For example, ensure all the
“104” labels face to the front, or to the right (depending which way the capacitor is orientated on
the PCB). This makes it much easier to inspect the PCB assembly later.
Take particular care soldering wires which connect to the ground plane. Despite the
“thermals” (a ground pad is connected to the ground plane by four thin traces, not a
continuous ground plane, to make soldering easer), the heat dissipation is still more, and it
can be harder to make a good joint.
Содержание QCX 5W CW
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