Elecraft K2 Owner's Manual - Manual (Page 77)

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LECRAFT ®
Keeping the K2 on its left side, slip the heat sink over the rear-
panel connectors and into position (Figure 6-33). Figure 6-34 shows
how the heat sink and associated hardware appear in cross-section.
Figure 6-33
Make sure that the four small holes in the heat sink line up with
Q7/Q8 and the 2-D block between them.
Press the Q7/Q8 mounting screws all the way back in so that they
protrude from the heat sink.
Use two chassis screws and two #4 lock washers to secure the
heat sink firmly to the 2-D fastener.
Secure Q7 and Q8 on the bottom of the heat sink using 4-40 nuts
and #4 lock washers. Do not over-tighten the nuts, as this may cause
the thermal pads to scrape against the heat sink, possibly causing a
short to ground.
Figure 6-34
Using an ohmmeter on a low resistance scale, check for a short
from Q7 or Q8 collector to ground. (This test should also be performed
any time the heat sink is removed and re-installed.) If a short is
measured, remove the heat sink and investigate the cause. The most
likely reason for a short is mis-alignment of a shoulder washer or
thermal pad. If a thermal pad or shoulder washer is damaged, it must
be replaced.
There are four more #4 holes in the heat sink: two on the bottom
and two on the back panel. Use four chassis screws to secure the heat
sink to the side panels and RF board at these locations. You may need
to adjust the positions of the 2-D fasteners on the side panels slightly.
Install the washers and finishing nuts that you removed earlier
from the antenna and key jacks. (The antenna jack hardware is shown
installed in Figure 6-34.)
Heat
Sink