Elecraft KRC2 Manual - Manual (Page 10)

10
Install 10k, 1/4 watt resistors (brn-blk-org) at R2 and R11 on the bottom side of the PCB.
__R2, __R11
Install the 40-pin IC socket at U1 on the bottom side of the board. The notched end should
be oriented toward the notched end of the PCB outline (pin 1 end, to the left). Solder just two
corner pins. If the socket is not sitting completely flat against the PC board, reheat these two pins
one at a time, pushing the socket down until it snaps into position. Then solder the remaining pins
of the socket.
Install U2, (MAX1406CPE or LT1039CN16) on the bottom side of the PCB. Orient the
notched or dimpled end toward the notched end of their PCB outline (pin 1 end, to the left).
Double-check the orientation before soldering. There is no need to trim the leads of U2.
Install resistor network RP1, 390 ohms (391), 8 pins, on the bottom side of the PCB. This
resistor network is symmetrical and can be installed in either orientation, but for consistency you
should orient it with the pin 1 end (black dot) toward pin 1 of the PCB outline (round pad, also
labeled "1").
Install resistor network RP2, 47k (473), 8 pins, on the bottom side of the PCB. This resistor
network should be oriented with the pin 1 end (black dot) toward pin 1 of the PCB outline (round
pad, also labeled "1").
Install low-profile crystal X2 on the bottom side of the PCB. This is a short 16.289 MHz
device. Make sure it is flat against the board before soldering. Use a minimum of solder so that it
does not wick through and cause a short on the opposite side of the PCB..
Locate the ground pad near X2. Insert a discarded component lead through this pad, then fold
it over the top of X2. Solder this lead at the ground pad, then solder it to the crystal can. Avoid
overheating the crystal.
Install electrolytic capacitor C15 (10 µF) on the bottom side of the PCB. The (+) lead of C15
must be installed in the hole marked "+". The (+) lead is usually longer than the (-) lead. The (-)
lead is identified by a stripe on the body of the capacitor.
Install transistor Q1 (J310) as indicated by its outline on the bottom side of the PCB. The
installed height of the transistors must be no more than 3/8" (9 mm). The top of Q1 must be no
higher than the top of C15. Use a minimum of soldering time (1-2 seconds per lead).