you have already soldered the center pin, you are at risk of creating a solder bridge and they are
quite hard to remove.
Similarly, solder the leftmost pin of Q1 first (ground), followed by the center pin then the right pin.
Check with the DVM for no short-circuits, AGAIN, after soldering.
Now the front and rear panels can be attached, using two screws in each panel to attach them to
the lid of the enclosure. Note that the PCB is “upside down” when it is installed in the enclosure. It
doesn’t mind. Remember, heat rises.
The bottom part of the enclosure is pressed into the top part and secured using four screws, two in
the bottom corners of the front panel and two in the bottom corners of the rear panel (see below
left). The top and bottom of the enclosure use a tongue-and-groove system on the long edges;
what this means is that the enclosure will only fit together properly one way round. If you find it
does not fit or the holes in the panel do not appear to line up properly with the holes in the
extruded bottom section, then check that you have the bottom section the right way round! You
might need to rotate it 180-degrees.
For now, DO NOT FIT THE BOTTOM part of the enclosure – you still need to complete the set-up
of the amplifier, which involves adjusting the R5 trimmer potentiometer!
Fit the BNC connector nuts on the rear panel. They do not need the compression washers. There
is no need to over-tighten the nuts. See below right.
50W QCX PA kit assembly
1.00q
41
