QCX+ Arrival!

The PCBs, Enclosures and various other parts arrived in 7 days door to door, including the weekend! Arrival was just after 11pm local time on Friday 19-Jun-2020. 15 boxes, total weight just under 300kg. 


This is the TCXO module (already factory-assembled, no SMD soldering to do) see http://shop.qrp-labs.com/qcxptcxo. It fits beautifully on the PCB, just as designed. The cut-out hole in the TCXO PCB fits over the top of the factory-installed Si5351A on the main QCX+ PCB. The TCXO is soldered in place of C2 and XTAL2 (which are NOT installed), using three wire off-cuts. Works great. 

Front panel assembly

These photos show the front panel assembly. The design is such that the buttons, LCD and rotary controls (encoder and gain potentiometer) are all at the correct height to fit through the front panel. 

The buttons are 12mm high with special button caps so that they protrude the right amount from the front panel. The 7x7mm latching push-switch On/Off button uses a smaller cap and is also at the correct height. The LCD module is soldered in place using a 1x16-pin header. It does NOT use a pin-header plug and socket arrangement like the original QCX - the LCD module is not now removable. Nor should there be any need, since there are no components in the 2mm gap underneath it. 

The specially manufactured 5K potentiometer is changed compared to the original QCX; the new potentiometer has a circular shaft with flat on one side, just like the rotary encoder. Not the "ribbed" shaft that is designed for a push-on knob. The new potentiometer shaft is a better fit to the supplied knob, the grub screw now fixes on to the flat part of the shaft and this ensures the white line on the knob is orientated correctly for minimum/maximum volume settings in an intuitive way. All available potentiometers had shafts that were too short for the knob to fit. To solve this problem we commissioned a custom-manufacturing batch of pontentiometers which have a 5mm longer shaft. 

As you can see it all fits together beautifully. 

Main PCB

Some photographs of how the main PCB looks... note the PA transistors bolted to the PCB so they use the PCB as a heatsink. 

Assembled PCBs

The two PCBs plug together using right-angled pin header plugs on the main PCBs and corresponding pin header sockets on the front panel PCB. 

Finished QCX+

Ooops I forgot to tighten the bottom left front panel screw....

QCX+ Dev kit

This is the QCX+ Dev kit http://shop.qrp-labs.com/qcxpdev which is supplied with 4x 12mm nylon hex spacers and 8x 6mm M3 nylon screws, to fit the dev board as shown, on top of the main QCX+ PCB. The photos also show an example of how to create interconnections between the main QCX+ PCB and the Dev kit PCB. There are 8pcs 2-way female pin header socket included and a 1x20-pin male pin header plug which may be broken into smaller pieces. Here I show just a 2-pin header installed to show the connection principle.