FW on radio: v1_02_000

I've run into a few issues with my QMX+. Initially, I had to repair some bad connections on T507 because I wasn’t getting a power reading.

Before fixing the power issue, I was able to receive just fine and tune the VFO without any problems. However, after powering the unit down one night, I found that I could no longer tune beyond the lower bands. It typically gets stuck on 160M and won’t let me tune outside the 1.8–2 MHz range.

The volume and tuning knobs show no unexpected activations in Diagnostic Mode via PuTTY. I can tune up and down within the 160M band reliably, and the encoder appears to function correctly—there’s no skipping, jumping, or erratic behavior. I can also scroll through the menus without any issues.

Under the oscilloscope, the tuning knob generates a pair of clean quadrature square waves when turning left and a different set of waves when turning right, using two probes.

Interestingly, if I enable Diagnostic Mode—either via the front panel or PuTTY—I can switch between bands and transmit. In this state, every PF (PF0–PF5) activates as expected, and I see a reasonable SWR (~1.10) and power output that matches what my Daiwa CH-501H meter shows when connected to a 100W 50Ω dummy load. So, the radio is clearly capable of tuning to other bands and transmitting on them—just not via normal VFO operation.

I’ve tried multiple factory resets, making sure to select “QMX+ 160–6m” with the left gray button. I also tried downgrading from v1_02_000 to v1_00_27 and performed factory resets at each step. None of this has resolved the issue.

Question:
Is there any kind of feedback loop or protection mechanism that would prevent the processor from allowing band changes or tuning beyond 160M, except when in Diagnostic Mode?

Thanks in advance for your help,
-Juan

开云体育