10W HF Linear PA kit assembly
1.00
4
possible (immediately after soldering the incorrect component). Again, a reminder: removing a
component and re-installing it later is often very difficult!
Components in the kit are installed vertically, to minimize PCB area and track-lengths. You will
need to bend the resistor wires as shown in the picture below. On the parts layout diagram, there
is a small circle around the hole where the body end of the resistor should be installed. This is not
critical (resistors don’t care which way around they are) but it is recommended, just to try to ensure
that the folded over wire-end of the
resistor doesn’t touch any other
wire or metal part.
Please refer to the layout diagrams
and PCB tracks diagrams and
follow the steps carefully.
The component colour coding of the layout diagram at every step of the assembly instructions is
as follows (kind of: components past, present and future):
•
Components shaded grey have already been installed
•
Components shaded red are the ones being installed in the current assembly step
•
Components shaded white are the ones which have not yet been installed
VERY IMPORTANT SOLDERING ADVICE:
when soldering a component pin that goes to ground,
you need to allow extra time with the soldering iron. Ground pads are separated from the
groundplane by what are called “thermals”, a gap between the pad and the groundplane which is
bridged in 4 places at 0, 90, 180 and 270-degree around the circle. This is standard practice.
However, you may STILL find that it is harder to solder ground connections, because the soldering
iron heat is dissipated away more quickly. If a component ground connection is broken it can
sometimes have catastrophic consequences. So please check and recheck, particularly with
ground connections.
3
ASSEMBLY
The PA board is mounted vertically on the rear PCB’s back edge. The PA transistor tabs and the
driver are bolted directly to the substantial heatsink provided in the kit.
Use a drill bit, twisted by hand, in each hole of the binocular cores, just to remove any
sharp edges, and prevent scratching the wire enamel.
NOTE: The two BN61-2402 binocular cores are supplied in a small labelled bag. This is
because they are visually identical to the BN43-2402 binocular core. Do not remove the
BN61-2402 from their small bag, or you would risk mixing them with the BN43-2402.
3.1 Parts list
This parts list shows the through-hole components to be inventoried and installed in the assembly.
Resistors
R201, 216, 217
220-ohm ¼W, red-red-black-black-brown (3pcs)
R203, 204, 209, 210
220-ohm ½W, red-red-black-black-brown (4pcs)
R202
22K, red-red-black-red-brown
