ELECRAFT K2/100, Руководство пользователя

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Install the following resistors near T1. Note: Two sizes of 10-ohm
resistors are to be installed. The first to be installed, R9, is the smaller
size, rated at 1/4 watt. The other 10-ohm resistors are much larger and
rated at 2 watts.
__ R9, 10 ohms, 5%, 1/4 W (brown-black-black)
__ R34 and __ R35, 10 ohms, 2 W
__ R19 and __ R20, 1.6 ohms, 2 W
__ R22, 300 ohms, 2 W
__ R21, 10 ohms, 2 W (form leads to fit given pad spacing)
Install an insulated jumper wire between the pads of R23. Use 1”
(25.4 mm) the solid-conductor #24 hookup wire and strip 1/4” (6.3 mm)
from each end.
Install relay K3, located near T2.
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In the next step, when installing capacitors C2A and C6D you may
find that the spacing of the leads is greater than the solder pad hole spacing.
If so, reform the leads as shown below. Be sure the capacitors stand no
higher above the board than shown.
5/8” (16 mm)
MAXIMUM
PCB
Install the following capacitors in the low-pass filter area:
__ C2E, 1000 pF, 500 V silver mica
__ C2A, and __ C6D, 1200 pF, 630 V polypropylene (6122)
__ C2C, 2200 pF, 500 V silver mica
Install the following capacitors, located in the area between the two
power transistors.
__ C58 and __ C59, 0.1 µF (104), 0.2" lead spacing
__ C80 and __ C81, 4700 pF (472), 0.25" lead spacing
Unwrap the heat sink and place it on a soft, clean surface to protect
the finish. Orient it with the speaker hole at top left and fins facing down
(see Figure 29 on next page). The raised area on the right side is the
pedestal , where the power transistors will be mounted. The PC board will
be mounted at the seven points marked H and S .
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The heat sink has a non-conductive, black oxide finish. To
ensure good electrical contact between the heat sink and PC board,
the finish will be removed at the seven points shown at right. When
working with the heat sink, be careful not to nick or scratch the fins
(on the opposite side).
Attach a portion of the supplied sandpaper (no more than 1/4
th
of the
sheet) to a flat piece of wood or a sanding block. The block should be at
least 4" long and 1" wide (10 x 2.5 cm).
Locate the two machined standoffs on the pedestal, labeled S in
Figure 29. Lay the sanding block across the top surfaces of both
standoffs. Keeping the block parallel to the pedestal at all times, carefully
sand off just enough of the black finish to expose the top surfaces of the
standoffs.
Do not remove any further material, since this may affect
proper spacing of the power transistors.
Use the sandpaper (but not the sanding block) to remove the finish
around the holes labeled H in Figure 29. The area of finish removed
should be approximately centered over each hole, and at least 1/4" (6
mm) in diameter.
Note: You can also scrape away the anodization with a
sharp tool or a hand mill (Dremel tool) with a wire-brush attachment. Be
careful not to cut down into the aluminum.
Locate the 7 set screws (4-40 x 1/2") and the small hex wrench.
Thread a set screw into each hole marked H or S , being very careful not
to cross or strip the threads during insertion. Tighten the set screws using
the hex wrench.
Do not over-tighten the screws or you will strip the
threads!
Thread 3/16" dia., 3/16" long standoffs onto the five set screws
marked H . Do not use lock washers. Tighten the standoffs using pliers,
but do not over-tighten.