ELECRAFT 13
4. Control Board
The Control board is the "brain" of the K2. It monitors all signals
during receive and transmit, and handles display and control
functions via the Front Panel board. The microcontroller, analog
and digital control circuits, automatic gain control (AGC), and audio
amplifier are located on this board.
Components
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Review the precautions described in the previous section
before handling any IC’s or transistors. These components can be
damaged by static discharge, and the resulting problems are often
difficult to troubleshoot.
Open the bag of components labeled CONTROL and sort the
parts into groups (resistors, diodes, capacitors, etc.). If any of the
components are unfamiliar, identify them using the illustrations in
the parts list, Appendix A.
Locate the Control board. It is the smallest of the three K2
PC boards, labeled "K2 CONTROL" on the front side, in the lower
right-hand corner. The lower left-hand corner is notched.
Open the bag labeled MISCELLANEOUS and empty the
contents into a shallow box or pan. This will prevent loss of any of
the small hardware while allowing you to locate items as needed.
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The Allen wrenches are located in a small bag with the
MISCELLANEOUS items. These wrenches may have been oiled
during manufacturing. Remove the wrenches and wipe off the oil, if
any, then discard the bag.
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There are five sizes of 4-40 machine screws provided with
the kit. The relative sizes of the screws are shown below for
identification purposes (not to scale). All of the screws are black
anodized except for the 7/16" (11 mm) screws. The 3/16" (4.8
mm) pan-head screws are the most numerous, and will be referred to
as chassis screws throughout the manual. There is only one flat-
head, 3/16" screw.
Flat-head, 3/16” (4.8 mm)
Pan-head, 3/16” (4.8 mm)
(chassis screws)
Pan-head, 3/8” (9.5 mm)
Pan-head, 1/2” (12.7 mm)
Pan-head, 7/16” (11 mm)
Identify all of the 4-40 screws and sort them into groups.
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