Presonus StudioLive AR12c
This time I’m servicing a Presonus StudioLive AR12c mixer, where the entire digital section wasn’t working. It quickly turned out that the power supply was damaged – specifically, the part responsible for providing +5V to the digital section (the DC/DC voltage converter). Apart from a few damaged electrolytic capacitors – one of which “exploded” and another at least bulged—the main problem with this power supply was a damaged GPM8023 switching IC, a cheap Chinese semiconductor.
Unfortunately, the original component is no longer available, but fortunately, it turned out that a functional equivalent is the CX8509 from CoreMicroTechnology (also from the Far East). I bought a module equipped with this IC (as it was the cheapest option), and it turned out that the module actually contained an MP1482DS IC – a sort of clone of a clone ;-). So in the end, we had a clone of an equivalent ;-).
Nevertheless, replacing the IC (and the passive components) brought the mixer back to life. Another matter is that the power supply itself is at least poorly designed…but I’ll leave that to Presonus engineers (or rather, their accountants).
