QMX kit
1 - board revision, Rev 2
2 – Bands,? High?
3 - build supply chosen, 12 volts
4 - Firmware version, 1_00_014?
5 - Any modifications during or after the build. No
Initially radio TX & RX fine with 2.8-5w output power and diagnostics via putty looked OK. I started adjusting LPF to even out TX power but it only made it worse. I got to the point where I could only get 1 watt out on all bands and terminal sweeps were all over the place.
After going over the board many times looking for errors, broken components, shorts and touching up solder joints I now have zero output on all bands with the “S” SWR on TX. Terminal sweeps are very poor, examples attached. Should I to start removing T401, T507 & LPF and check for shorts? I just have a DVM and limited knowledge on fault finding. I have built a QDX and QCX-mini previously.
OK, I know I should have left it alone when it was working fine! But I’d really appreciate some guidance as to where to look first. I feel that I’m just making the situation worse at the moment.
Many thanks,
Roger MW0IDX
Roger Dallimore