ELECRAFT KAF2 Instrukcje Operacyjne Pobierz pdf (Strona 9)

Page 9

Construction Manual for the K2DI v.III and K2DI-PCI boards © EA3BLQ - Revision June 2005

Picking the received AF signal up from P2 at the

KAF2 or KDSP2 boards

Caution: If you, to take advantage of the filtering provided by either circuitry of the KAF2 or KDSP2 devices

and/or because the connection for the K2DI v III.2 is handier, decide to pick the received AF signal up from the P2

connection at the KAF2 or KDSP2 boards, instead of picking it up from the auxiliary AF connection provided at J5

on the RF board, please bear in mind the following facts:

a.- In both cases the K2’s audio circuit is the very same balanced one, but

b.- On the RF board, the 3 pin distribution at J5 correspond to pins 1 and 3 for the audio lines and GND is

connected to pin 2.

c.- On the KAF2 or KDSP2 boards, the 3 pin distribution at P2 correspond to pins 1 and 2 for the audio lines while

the GND connection is located at pin 3.

Obviously the 3 pin female connector you may prepare to connect J4 at the

K2DI to J5 on the RF board cannot

be used for connection to P2 on the

KAF2/KDSP2 boards. It would produce a short.

To avoid this risk I have prepared the special male-male header shown on the

image at the right, which is to substitute the one provided by Elecraft with

either of their devices.

Should you have the original P2 header already installed you are to desolder

it taking outmost care in the process so as not to damage the soldering pads.

The square soldering pad, near the down board’s edge, corresponds to pin 1.

The special header is to be introduced for installation into the KAF2 or KDSP2

through the bottom side of the board, taking care to position its pin 1 through

the square soldering pad. Check before soldering. The 3 equal pins with the

plastic holder go on the bottom side. (See pictures below)

Soldering is done on the top side of the board. Before soldering check the

header’s positioning once again and, if it is ok, solder only pin 3. Check the

positioning once again and see that the plastic holder is flush with the board

and that the pins are perpendicular to the board and parallel to those of P1. If

any correction is necessary please do so by reheating the pin 3 solder. If it is ok please go on soldering pins 1 and

2, but taking care to use a minimum amount of solder, just the necessary to secure a good contact between the

board and the pin. Use a magnifying glass to check the joints.

Once finished soldering please prepare the locking tab by cutting out the borders of the indents at its bottom to

allow more contact field for the pins and perhaps you will have to shorten its base by a couple millimeters to allow it

to sit flush on the board when installed in the two pins.

Special header installed w/o locking tab. Locking tab installed. Showing tab and pin 3

(GND) solder.

This pick up set-up also applies for the KAF2 audio filter board.

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ELECRAFT KAF2 Instrukcje Operacyjne Strona 9