Roland MIDI Input selector MPU-104

Roland MIDI Input selector MPU-104   No serial number   Condition: Excellent

• Latching push-button selection of one of five inputs to an output.
• Channel one has highest priority
• Convenient “circuit diagram” on the lid
• Does not need power for the MIDI, only the channel indicators need an external PSU
• Standard Roland (Boss) 9v DC power supply (pin is negative).  PSB-1U or similar.