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Assembling.
pa0nhc ARDFrx80-7 20140914

To prevent "hand effect" a sheet aluminum foil 10cm x 4cm must be glued in the bottom of the ABS box, located under the PCB between IC1 and IC2. It should connect to the PCB's bottom copper mass via the central M3 screw. Three nuts on top of each other on each M3 scew can serve as spacer between the PCB and the ALU screen.



Prevent damage to active components : Solder active components (diodes, tranistors, ICs) as last of all.

IMPORTANT (only for home made PCBs which do not have metalized holes) :

Solder all "ground"-connections of resistors and small capacitors on both sides, bottom copper AND top copper.

C105 must also be connected to the bottom tracks. Therefore both wires of C104 have to be soldered on top and bottom copper.

In order to connect the "hot" side of C110 to the bottom track, the corresponding wire of C6 has to be soldered on top and bottom copper.
Another way is:
Make a "via" : before you place and solder C6, make the connected to C110 a little wider and solder a small piece of thin wire in the hole.

In order to create a low-Z mass connection for Xt, be sure you soldered mass of C204 at top and bottom copper. 

1. FIRST place all low profile passive components (resistors, small capacitors, trimmers and the link) on the top copper and solder them.

2. Then place all remaining bigger passive components on the top copper (elcos, chokes, coils. cristals) and solder them. 
Quickly solder the metal can of the xtal near R14 to the top mass plane.

    Before soldering any active components, prevent static damage as follows :

3. Solder FA3 and FA5 temporarily to mass.
4. Solder "Tunepot-mid" temporarily to mass.
5. Solder "Gainpot-mid" temporarily to mass.

6. Connect the mass of the soldering iron and your body to both PCB mass planes via a souple piece of wire.

    REM: At Fets 102 / 103 / 104 / 5 : observe GSD / DSG / GDS / SGD pinning of different types (Equivalents are: BF244, BF245, BF246 and BF247. They only differ in pinning. Use them as available). For correct pin connections see markings on the top silk of the PCB. Keep the transistor pins short.

7. Insert from the top copper D1, 2, 3, 4, Fet5, 103,104, T1, VR1, Ic1, Ic2 and solder them.
REM: do not use an ICholder for IC1, but solder it directly into the PCB, with a drop of heath paste between it and the PCB.
         Together with using foilCs for C3 and C46, it results in the best oscillator temperature stability.

8. Then place and solder at the bottom copper the SMD varicaps (CD1, 101,102) and Fets 1 / 4 .
    REM: Check that the SMD components are positioned with their legs bend TOWARDS the PCB surface.
              The broad leg of Fets 1/4 is source, it should make contact with the PCBs mass connection.
              CD1 : marking is cathode. The other side must be in contact with mass.
              At CD101 / 102, the mid leg is cathode. The other two are anode. Only one anode is connected to the circuit.
              The other anode "floats". See picture.

9. Check if all components are placed.
    Check all solderings ( ! ) and check for short circuits
using a magnification glass.

10. Connect all external components (Sa, Pb, Fa, Tune, Gain, Bat, Phone) with supple wires.
REM: keep all wires away from the oscillator circuit environment, as a little movement could detune the receiver. After testing, fix the wires with some glue to hold them steady in place.

11. Then remove the temporary mass connections from FA3,5, Tune and Gain.

12. Goto "Setup".