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These PASCAL S-PRO2 units are notorious for the small electrolytic capacitors drying out, causing excessive ripple voltage and hence not stable enough DC voltage for the SMPS to start. Test the ESR of the small electrolytic capacitors, especially the PSU ones. I have a BIG collection of class D amplifier modules, and as if by design, they install the DC/DC converter IC Bias capacitor either near a heatsink, or where there is little to no airflow! (Planned obsolescence most likely)
It seems capacitors of the smaller sizes like 10uF 50v / 63v, 22uF 50v / 63v, and 100uF 25v / 35v for example, are usually the most likely ones to measure a very very high ESR (Equivalent Series Resistance) These capacitors don't even have to have a bulging top - the high temperature operation for an extended period of time is enough to push them past their rated life.
Of course, there are other issues that can occur with these Pascal modules, however, most of the ones I have come across just needed some new capacitors.
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