: If the sticker is missing, some units may have the serial number handwritten or stamped on the internal chassis or PCB, though this requires opening the unit. Vintage Synth Explorer Forums Product Codes & Serial Numbers (Software VST)
The Korg M1 serial number serves several purposes: Korg M1 Serial Number
: Look for a black sticker or plate near the input/output connectors. It usually lists the model name along with the unique serial digits. : If the sticker is missing, some units
button while turning it on to verify the internal ROM version. Sweetwater Further Exploration M1 Owner's manual - Korg : If the sticker is missing