Elecraft K2 Owner's Manual - Manual (Page 18)

E
LECRAFT ® 17
Install crystals X1 and X2 so that they are flat against the board.
X1 is 5.068 MHz and is located near the notch in the lower left-hand
corner. X2 is 4.000 MHz, and is located near the center of the board.
Solder the crystals.
Prepare two 3/4" (19 mm) jumpers wires from discarded
component leads. These short jumpers will be used to ground the
crystal cans in the next step.
i
Grounding the crystal cans in the following step is required to
ensure proper crystal oscillator performance.
Referring to Figure 4-3, insert the jumper wires into the grounding
holes provided near X1 and X2. Fold each wire over the top of the
crystal and solder it to the top of the can. (Only a small amount of
solder is required.) Then solder and trim the wire on the bottom of the
board.
X1 X2
Figure 4-3
i
The voltage regulators, U4 and U5, will be installed in the
following steps. These regulators have different voltages and must not
be interchanged. Check the labels before soldering.
Install U4 (LM2930T-8) and U5 (78M05, 7805T, L7805, etc.),
forming the leads as indicated (Figure 4-4). Fold the pins over the
shaft of a small screwdriver to create smooth bends. After inserting the
leads into the proper holes, secure each IC with a 4-40 x 3/8" (9.5 mm)
machine screw, #4 lock washer, and 4-40 nut. (These regulators may
have either plastic or metal mounting tabs.)
Use smooth
bend, not sharp
Figure 4-4
Solder the voltage regulator ICs.
Trim the IC leads as close to the PC board as possible.
Install a 40-pin IC socket at U6. (The microcontroller will be
inserted into the socket in a later step.) Orient the notched end of the
socket to the left as shown on the PC board outline. Bend two of the
socket’s diagonal corner leads slightly to hold the socket in place, then
solder only these two pins. If the socket does not appear to be seated
flat on the PC board, reheat the solder joints one at a time while
pressing on the socket.
Solder the remaining pins of the 40-pin socket.