Figure 14 Trimcap Install; Figure 15 Bd139 Location - ozQRP MDT Construction Manual

Step 8: trimmer capacitor
The trimmer capacitor supplied is quite small and has one lead electrically connected to the
screwdriver adjustment slot. Use a multimeter to determine this pin and solder to the hole in
the PCB connected to the ground plane. If you find the leads too wide for the PCB holes, simply
trim them down with sidecutters before inserting. The earth pin of the trimmer capacitor is
highlighted in Figure 14.
Earth pin

Figure 14 Trimcap install

Step 9: trimpots
Note that the carrier balance trimpot is a 500 ohm multi-turn vertical mount while the
Microphone gain trimpot is a 5K horizontal mount type.
Step 10: transistors
The 2N3904 transistors are orientated to match the screen silk component overlay. The BD139
transistors are mounted so that their Bases face the left hand side of the PCB when viewed from
the front as shown in Figure 15.

Figure 15 BD139 location

MDT Construction Manual – Issue 2 Page 25