QRPKits DC20A, Manual

Page: 7 / 18

2/14/2007 Page - 7
Tips and Info for First Time Builders
Installing parts:
You can insert several parts at a time onto the board. Parts should be pressed flush to the top of the board. The
exception are the transistors which should stand off the board by about 1/8” due to their three legged nature. Once
you insert the part, kink one of the leads over slightly to keep it from falling out of the board when you flip the board
over to solder.
The .1 uF caps used in the kit have formed leads, so these will not sit quite flush to the board. Several of the disc
caps have lead spacing larger than the pads on the board. You can reform these leads with your pliers so they will
sit flush to the board.
Once you solder a part in place, clip the lead nearly flush to the board. Clip at the top of the little fillet of solder
which forms around the lead.
Finding the right part.
A picture at the bottom of the parts list on the previous page can be used to help identify some of the parts. The
parts not shown should be obvious or deduced by the process of elimination. The numbers identifying the
monolithic caps (mostly yellow or blue in color) can be hard to read. The use of a magnifying glass can help you to
see them. In addition to the part value of the capacitor, there are a number of other letters and numbers printed on
the part. Simply look for the three number group which matches the value your looking for, 331 for 330 pF, 104 for
.1 uF, 681for the 680 pF cap and so on.
IC pin 1.
The outline on the board for the ICs has a “V” notch on one end. This indicates the pin 1 end of the IC. If a socket
is used, there is also a notch on one end of the socket. This end goes over the V notch outline on the board.
Finally, pin 1 of the IC is marked with a round dimple or dot. This end of the IC will go towards the notch on the
socket or “V” on the outline.
Soldering
There are two important things which need to be done to ensure the successful operation of a kit. One is getting
the right part into the proper place on the board. The second is good soldering. To ensure a good connection, the
soldering iron should touch both the component lead and the circuit board pad it’s to be soldered too. Heat the
connection for just a second, then put the solder to the iron/pad/lead junction. Allow just enough solder to flow to fill
the hole and wick around the lead. Go easy on the solder, you don't need a whole lot. If you use a thin solder like
0.02” instead of the more common 0.032” type, you have better control of the amount of solder used. For parts
which connect to the ground plane, you may have to heat the connection a little longer.
Coils and Transformers
You may find it convenient to wind and prepare all of the coils and transformers before you start inserting parts.
That way you don’t need to stop and possibly loose concentration to wind and them for installation. See page 5 for
band specific details.