Vintage Harmony H500 Electric Guitar Combo Amplifier Amp w/ Original Jensen

Welcome! Right now, you are looking at a super cool vintage amplifier.
This is a Harmony H500 electric guitar combo amp.
It's in good overall aesthetic condition, and even includes its original Jensen speaker.
It powered on, but I was only able to produce a "buzzing" noise. As such, it is listed for parts/not working.
Hopefully this is an easy fix for someone in the know.
Thanks for looking.