32 ELECRAFT
6. RF Board
Most of the K2’s receiver and transmitter circuits are located on
the RF board, including filters, oscillators, and RF amplifiers. The
front panel and Control boards plug into the RF board, and the
chassis pieces are designed to form a tight enclosure around it (see
photos in Appendix D). In addition, many option boards plug
directly into the RF board to minimize wiring.
Assembly and testing of the RF board is broken into three parts:
Part I: The DC and control circuits are installed so that the front
panel and Control boards can be plugged in and tested. The I/O
controller (U1 on the RF board) is also installed and tested at this
time. Once this phase of assembly is completed, you’ll have the
K2’s built-in test equipment available for testing and aligning the
remaining circuits.
Part II: Synthesizer and receiver components are installed and
tested. By the end of Part II you’ll have the K2 receiving on 40
meters.
Part III. Transmitter components and all remaining filter
components are installed. The K2 is then aligned on all bands.
Components
i
Review anti-static precautions before handling transistors
or ICs.
Open the bags labeled RF and sort the components into related
groups. In later steps you’ll sort some of the components according
to value to reduce the likelihood of assembly errors.
Locate the RF board and place it in front of you with the
component side up (the side with most of the parts), and the front
edge facing you (the edge with the irregular cutouts). Throughout
this section we’ll refer to the different areas of the board in terms
of their proximity to you. For example, "front-left" means the
corner closest to you on the left.
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