History of Yamaha Guitars", a good but far from complete book on Yamaha guitars, gives the following serial num..."> History of Yamaha Guitars", a good but far from complete book on Yamaha guitars, gives the following serial num...">

Asl50 Lac921p Rev 10 Schematic Exclusive

The schematic shows a pi-filter (C1, L1, C2) with a surge-rated varistor (MOV1). Rev 10 adds a 10Ω NTC thermistor (TH1) in series with the live line—previously omitted. This suggests the Rev 10 design addresses inrush current issues from capacitive loads.

: Common issues involve shorting in the 19V primary MOSFETs or failures in the SIO chip input/output voltages. asl50 lac921p rev 10 schematic exclusive