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Re: QCX Mini On Screen Measurement Not Changing #bpf #troubleshooting

 

OK Jake, I think you may have an oscillation?in one of the audio filter stages ... IC8A or B or IC9B. But first, since you see the different stuff every time you turn it on, I think it would be a good idea to do a Factory Reset (Menu 7.13) just to make sure there isn't some firmware glitch causing this.If that doesn't do it, then a scope may be needed to find which stage (if any) is oscillating. ... Good luck ... Ron


On Sat, Feb 4, 2023 at 1:38 PM <jake__donnelly@...> wrote:
IC10 gives 5.8V on all pins except for 0V on pin 4 and 12V on pin 8.

The volume is indeed very loud, it is only bearable to wear the earplugs in maybe the lowest 5% of the volume knob travel.

Also, since attempting to tune the BPF for the first time, now almost every time the device is restarted, the same sound heard during BPF tuning is heard after startup (once the welcome screen disappears). This sound can be controlled by the volume knob and is not unbearably loud. If the exit key is held down, or the menu is accessed, this disappears completely however, if the exit key is held down, the sound returns for a single 'dit'.

On another note, each time after restarting the device, the multiplier in the upper right corner of the BPF tuning screen is (vastly) different even though no change has been made to the variable capacitor.

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