You should be able to check the power supply voltage both connected and unconnected to the synth circuit boards. You may see higher voltages when disconnected, depending on the amount of expected loading of the circuit board. But if you are seeing voltages which are roughly close to the right voltages, and not zero, you have a working power supply. Those voltages themselves are safe, although obviously exercise due care when probing the power supply to avoid the AC voltage supply. Leigh -- Leigh M. Smith mailto:leigh@leighsmith.com http://www.leighsmith.com
Message
Re: Yamaha Electone EL500 repair
2017-04-25 by Leigh Smith