Is there an internal switch setting on the Yamaha DGX500 to allow the output/phones port to have both the internal speakers kept on as well as the output to a pa?

Thank you...Nigel gave me your name...MikeF

Mike,
There is not a switch or internal switching to have both the internal and external speakers working. You must use the headphone jack with a stereo insert cable to play through an external amplifier and speakers or a PA.
George Kaye
Kaye's Music Scene
Reseda, California