Help Please: Roland XP-30 line out noise unless headphones plugged

Hi all, new member here. My XP-30 has a buzz at 13KHz our if the output jacks. However, upon troubleshooting I found out that

  • the buzz is there unless the headphone jack is plugged in
  • there is no buzz out if the headphones

My hypothesis is that it may be the power supply unit, but I am completely ignorant on this so looking for help.

I also tried searching for this power supply and strangely it doesn’t exist in the Syntaur page. If this is the problem, would a power supply from an XP-50 work?

I would definitely check the electrolytic capacitors on the power supply and the main board, the XP series were known for the problem of capacitor failure here which affect the sounds output. It’s worth looking if you can see any that have leaked or are bursting