The Juno-Di uses an external 9V DC adapter, but internal regulators (5V for digital, 3.3V for CPU, and analog rails) can fail.
If the issue is physical, such as "dead" keys or jumping values, internal work is required. roland juno di service manual work
Before you even open the PDF or turn a screw, you must understand the risks. The Juno-Di uses an external 9V DC adapter,
: Dimensions (1021 x 292 x 103 mm), weight (5.0 kg), and power requirements (DC 9V, 1000 mA). 2. Panel Layout & Parts List but internal regulators (5V for digital