10W HF Linear PA kit assembly 1.00 15
Identify the pairs of windings. This could be confusing: now the windings CROSS when they are
inserted into the PCB holes.
Put another way: notice that the outline of the toroid
goes horizontally across the PCB. One pair of
twisted wires comes out on the upper side, the other
pair of twisted wires comes out on the lower side.
The upper two twisted wires are put into the upper
two holes; the lower two twisted wires are put into
the lower two holes. But there is an extra wire swap
such that the electrical connectivity is as shown by
the orange lines in the diagram.
Before cutting or soldering the wires, check again
very carefully, with a DVM touched to the wire ends,
that you have continuity between the two pairs of
points, as indicated by the orange lines. Only when you are totally sure the four wires are in their
correct holes, cut them to 2mm protrusion, scrape them a bit with the wire cutter, then solder them
(for at least 10 seconds).
For a continuity test to make sure that the four
wires have been properly soldered, simply
connect the DVM across the pads for C213.
If there is DC continuity this verifies that all four
wires are correctly soldered to their pads.
It does NOT verify that the 4 wires are in the
correct 4 holes – you will have had to correctly
identify the wires as described.
If there is no DC continuity then go back and
check the soldering of the 4 wires (and check
that the enamel was properly scraped/burnt off).
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General