Re: New QMX+ Calibration victim
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Continuing my own thread :-) Troubleshooting of my SSB calibration casualty QMX+ continues. After lowering the external PSU voltage limit a little?bit furher?to 7v?and lowering the current limit to 250mA I dared testing to allow the QMX+ to be powered on long enough to access the built-in diagnostics page. As suspected it shows that the 5v regulation doesn't work as it shows the 5v to be 5.6v at the same time as the SMPS duty cycle is 0%.? The sensing part seems to work though as it appears to try to lower the voltage by using low duty cycle.? Unfortunately as I'm looking at the schematic for the QMX+ PSU, I don't understand how it's supposed to work. Is there a description of this available somewhere? For example, which signals are inputs and which are outputs?? I assume the "5V PWM" is an input from the CPU. If this is low, then Q106 does not conduct, leading to Q108 also not conducting??
Best Regards Jonas - SM4VEY
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