Elecraft K2 Owner's Manual User Manual

Page 21

LECRAFT

Before handling any IC, touch an unpainted, grounded

metal surface or put on a conductive wrist-strap.

Locate U2, an 8-pin IC, part number LM833. (LM833 is the basic

part number. There may be an additional prefix or suffix or other
markings.) This and all remaining ICs on the Control board are Dual-
Inline Packages, or DIPs. Referring to Figure 4-10, identify the
notched or dimpled end of the IC. IC pins are counted starting from
pin 1 (as shown below) and going counter-clockwise.

Pin 1

Notch

Pin 1

Dimple

Figure 4-10

Straighten the leads of U2 (see Figure 4-9).

Install U2 in the orientation shown by its PC board outline, near

the upper left-hand corner of the PC board, but do not solder it yet.
Make sure the notched or dimpled end is lined up with the notched end
of the PC board outline. Even though the outline is covered when the
IC is installed, you can still verify that the IC is installed correctly by
looking at pin 1. The PC board pad corresponding to pin 1 will be
either oval or round.

You may overheat the IC pins or PC pads if you take an

excessive length of time to solder. After a few tries, you should be able
to solder an IC pin in about 1 or 2 seconds.

Bend two of U2’s corner pins out slightly on the bottom of the

board to hold the IC firmly in place, flat against the top of the board.
Find pin 1 and verify that its pad is either round or oval. Once U2 is
properly seated, solder all eight pins, using a minimum of solder.

Install the ICs listed below. Bend the pins to hold each IC in place

as you did with U2, but do not solder until the next step. The notched
or dimpled end of each IC must be aligned with the notched end of its
PC board outline.

Note: For U1, the IC type supplied may be either NE602 or SA602.

__ U1, NE602

__ U3, LM6482

__ U7, 25LC320

__ U8, MAX534

__ U9, LM380

__ U10, LMC660

Check the orientation of pin 1 on each IC by looking at the

associated PC board pads, as before. Then solder all of the ICs.

Locate the microcontroller, U6.

Straighten the pins of U6 (see Figure 4-9). With a large IC such as

this, you can hold the IC body at both ends as you re-form each row of
pins.

When the microcontroller is pressed in its socket, you must be

careful to avoid jamming its pins. Make sure that all pins are lined up
with the associated holes in the socket before pressing down on the IC.
Watch the pins on both rows as you press down, re-aligning them with
the socket holes individually if necessary.

Insert the microcontroller, U6, into its socket. Make sure that

pin 1 on the IC itself is lined up with the pin 1 label near the lower
left-hand corner of the PCB outline. Note: The revision label on the
IC (usually white) may not be oriented the same direction as the text
printed on the IC. Do not use the label as a guide--use the notch or
dimple to identify pin 1.