QRP Labs QCX 5W CW, Руководство по сборке

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QCX assembly Rev 1.08
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A jeweller’s loupe is really useful for inspecting small components and soldered joints. You’ll need
a fine-tipped soldering iron too. It is good to get into the habit of inspecting every joint with the
magnifying glass or jeweller’s loupe (like this one I use),
right after soldering. This way you can easily identify any
dry joints or solder bridges, before they become a
problem later on when you are trying to test the project.
Triple check every component value and location
BEFORE soldering the component!
It is easy to put
component leads into the wrong holes, so check, check
and check again! It is difficult to de-solder and replace
components, so it is much better to get them correctly
installed the first time. In the event of a mistake, it is
always best to detect and correct any errors as early as
possible (immediately after soldering the incorrect component). Again, a reminder: removing a
component and re-installing it later is often very difficult!
All of the resistors in the kit are installed vertically, because PCB space is limited. You will need to
bend the resistor wires as shown in the picture below. On the parts layout diagram, there is a
small circle around the hole where the body end of the resistor should be installed. This is not
critical (resistors don’t care which way around they are) but it is recommended, just to try to ensure
that the folded over wire-end of the
resist
or doesn’t touch any other
wire or metal part.
Please refer to the layout diagram
and PCB tracks diagrams below,
and follow the steps carefully.
Assembly steps will be in the order of smallest to largest components. I follow the order
semiconductors, capacitors, resistors and finally all other (generally larger) components. It is
probably unnecessarily thorough and complex to build the radio one stage at a time and test each
stage one by one… I recommend just install everything then power up.
As per standard QRP Labs practice, the ATmega328P microcontroller has a 28-pin DIP socket in
case you may wish to subsequently replace it for firmware upgrades etc. The Si5351A and
FST3253 ICs are only available in surface mount packages so these are already soldered to the
PCB for you, at the factory. All other components used are all leaded through-hole packages, and
all are installed on the top side of the PCB.
Some people like using IC sockets, some don’t. Undoubtedly there is a cost impact, of course.
Personally, I believe that on average, the use of IC sockets causes more problems than it solves.
They create the potential for bent pins that don’t make contact properly, hidden shorts under the
socket, issues with increased lead length, etc. Accordingly, the remaining ICs are soldered directly
into the PCB without IC sockets. Please forgive me if you disagree.
You may find it convenient to inventory the resistors and capacitors and sort them by value, so
that you can easily find the correct ones as you work through the assembly steps.