QRP Labs QCX-mini CW, Руководство по сборке, Страница: 71 / 121

If you want to use a small loudspeaker you will need to ensure this is an “amplified speaker”
because the audio output will not be strong enough to drive a speaker directly.
3) Antenna system
The RF output is a filtered 50-ohm BNC output for connection to a usual antenna system
(antenna, and matching unit if applicable).
4) Straight key or paddle
To operate the QCX-mini transceiver a straight key or paddle should be connected to the
appropriate jack, having a 3.5mm stereo jack plug. The shield (or main body) is ground. It
does not really matter which way around the tip and ring connections are (to dit or dah of
the paddle) since if they are the wrong way, there is a menu configuration item to swap
them around. Similarly if using a straight key, you can select in the firmware either tip, ring
or both for the connection; this allows use of a 3.5mm mono plug when using a straight key.
3.45 Notes on fault-finding for the QCX-mini
If your QCX-mini doesn’t work at all, or doesn’t work properly, don’t panic. This is a KIT and
as such, often things may not go perfectly as planned and some fault-finding is necessary.
The following are some tips to help.
1) On first power up, the QCX-mini may look dead, totally dead. No backlight on the
LCD module, and no text. This is probably OK! The backlight is controlled by a menu
item (in menu 7, the “Other” settings menu) and if that is OFF, then this explains why
the backlight is off. Seeing no text on the display is also normal until you have
adjusted the LCD contrast potentiometer R47.
2) You can remove the Controls board to do certain fault-finding. Since R46 (10K
resistor) was thoughtfully placed on the main board, not on the plug-in controls
board, this means that if you remove the Controls board, the processor will not
register any phantom button presses. The radio will remain in whatever state you put
it in, until you plug back in the Controls board. Removing and inserting the Controls
board can be done while QCX-mini is switched on.
3) If you remove the Controls board however, you are also necessarily interrupting the
audio signal path because you have removed R36, the gain control potentiometer.
Therefore no audio signal will reach IC10 and there will be no audio output.
4) You can remove the Display board and the QCX-mini will continue to work just fine –
only you won’t be able to see anything on the screen, of course. This can be useful
for accessing the main board to check signals at various points. If you plug in the
LCD module again while the QCX-mini is powered, you will NOT see any sensible
display until you cycle the power, because the display module requires a certain
initialization sequence.
5) Always connect a 50-ohm dummy load during testing or investigation!
6) There is a thorough trouble-shooting guide here:
http://qrp-labs.com/qcxmini/trouble.html – it is written originally for the QCX
transceiver but the circuit is the same, so it is equally applicable to the QCX-mini.
7) There is a trouble-shooting YouTube video see
http://qrp-labs.com/qcxmini/troublevideo.html , which explains how to use low cost
QCX-mini assembly Rev 1.05
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