Korg Lambda ES-50 - D keys broken

I’ve recentl dug out an old 'Korg Lambda ES-50 ’ from storage, it was mistreated in my youth and is in a sorry state. i’m hoping to revive it and at least make it functional again.

There’s two main issues to fix …

  • Every d note makes a non pitched sound , like a detuned oscillator , a non pitched noise. I’m wondering what could be the source of this issue is it likely a component that needs replacing or a dodgy connection or wire somewhere? Does anybody have an idea about this ? Can provide audio samples if it helps identify the issue.

  • 4 keys are snapped - I guess I can source these online somewhere these days, any recommendations for suppliers to UK ?

Thank you !