QRP Labs QCX 5W CW, Assembly Instructions Manual

Page: 53 / 138

QCX assembly Rev 1.08
53
toroid’s 39 windings. Count the windings to make sure you have 39. When you are sure
everything is fine, cut the wire leaving about 3cm of wire free at the end.
8) The remaining steps show the transformer installation on an otherwise empty
PCB, to make the explanation clear.
Thread the original start of your winding (from
step 1) into hole 1 in the diagram. Thread the final end of your winding (from step 7) into
hole 6.
9) Twist these two wires under the board to keep the toroid in place while you deal with the
remaining wires.
10) Now cut the 3
rd
loop (the one nearest the end of the winding work), and un-twist the
twisted section you made near the toroid body.
11) When you cut the loop, you therefore created two wires. One of these came over the top
of the toroid, and you can easily verify that this is the one which has three turns through
the toroid then passes through hole 6. So, insert this wire into hole 5. Once again to be
clear: you should now have a winding of three turns
(which is labelled “secondary 1”,
above), with one end inserted into hole 6 and one end inserted into hole 5.
The other wire came from UNDER the toroid. You must push this wire towards the toroid
and pull it out through the centre hole of the toroid. Now thread it through hole 4.
Under the board, twist the two new ends of wire together to keep them in place.
12) Next cut the 2
nd
loop, and un-twist the twisted section near the toroid body.
13) Similar to step 11; the wire which came over the toroid body has three turns then goes
into hole 4, which you did in step 11. Insert this wire-end into hole 3.
The other wire end that came from under the toroid body should be gently pushed toward
the toroid, and pulled up through the centre hole of the toroid. Insert that wire end into
hole 8.
So now you have the “primary” winding consisting of three turns, between holes 3
and 4.
Twist the two new wires under the board again, to keep everything in place.