Hello there. Finished building my QMX a couple of weeks ago, and just wanted to share my experiences in case of any interest.
As others have mentioned, I did find it very challenging, with the very fine soldering work, especially with my 70 year old eyesight!
I was concerned about downloading the firmware, because I'm not exactly computer savvy, so I was delighted when the radio 'flashed up' without any smoke:)
However, although apparently receiving very well, there was no transmission. After resoldering every dodgy looking joint I could see, and there were a few, I found a broken SMD 5.1k resistor
R504, and after studying the circuit, decided this may be the cause of no transmit. I replaced it with a 5.6k SMD resistor off a junk box pcb, and Lo and Behold, we are up and running!!
After my initial joy and delight, and first qso, I had a couple of problems pop up.
1. Very erratic audio, randomly going very high and being un-controllable with encoder rotation.
2. Frequency jumping in large increments, and sometimes action of encoder reversing ie cw rotation of encoder, frequency decreasing and ccw increasing.
I tried a factory re-set, just in case, but this made no difference. As both encoders seemed to be 'playing up', I thought I would check all soldering of encoders to control pcb, and headers on both control and main pcb. All resoldered,
Fitted diode between L503 and C508 as per Hans' mod instructions. All now seems ok - fingers crossed. I have had numerous qso's now, on 7Mhz ,10Mhz and 14Mhz, all cw and have had great success. Congratulations Hans on a great little radio! I will buy you a coffee when I find out how the machine works:)
I have spotted a couple of glitches, but these are well written about already, so I wont repeat.
Going on holiday to Texas USA in a week, so will take the radio with me and see how I get on.
73's Martin G0ILZ
