I'd imagine someone more familiar with electronics possibly could have figured out what specific component was wrong and replaced only that for an even smaller fraction of the cost.

Probably electrolytic capacitors (usually in the tens of cents each, or less.) They are the #1 suspect in any electronics as they have the most well-known and finite lifespan of all parts. They became particularly infamous for failing when this happened: https://en.wikipedia.org/wiki/Capacitor_plague

The term has even created a noun in other languages: https://sv.wikipedia.org/wiki/Kondensatorpest