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SiriusHardware · 11th Feb 2019, 2:14 pm

That's a relatively common failure mode associated with semiconductor power devices (any type) if they run warm and are regularly turned on and off, especially if they are fixed to a headsink as well as soldered to the pads of the PCB. As the component warms up, its leads expand a little and as it cools down, they contract a little. Eventually (after many years) this results in a perfectly circular ring-shaped crack in the soft solder surrounding one or more of the leads of the device.

So when you get a chance to look at the regulator, look at least twice at its solder joints on the print / track side of the PCB, or just resolder them regardless.

11th Feb 2019, 2:14 pm	#14
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,571	Re: Yamaha CLP411 Electronic Piano That's a relatively common failure mode associated with semiconductor power devices (any type) if they run warm and are regularly turned on and off, especially if they are fixed to a headsink as well as soldered to the pads of the PCB. As the component warms up, its leads expand a little and as it cools down, they contract a little. Eventually (after many years) this results in a perfectly circular ring-shaped crack in the soft solder surrounding one or more of the leads of the device. So when you get a chance to look at the regulator, look at least twice at its solder joints on the print / track side of the PCB, or just resolder them regardless.