One more update to this project. I spliced the audio cables, which got the speakers working, but they were very quiet. I read somewhere else online that the amplifier IC in powered PC speakers and wear out over time and lead to this symptom. I thought that sounded weird, but worth a shot. Before that I tried replacing the capacitors on the amp, but it made no change. The IC these speakers use is a
TEA2025B. I coudln't find that chip very cheaply on its own, but did find it as part of a component in a
complete amp, including heat sink for $7 shipped. There may be pin compatible alternatives available more cheaply too.
I swapped the chip from that amp with the one in the Packard Bell speakers and sure enough that solved the problem. They're now as loud could be expected. The audio quality still sucks by most standards. There's a bit of hiss when no audio is playing and there's no low end to speak of. The drivers are 3.5"x2" 4 Ohm. I tried looking for modern alternatives that might be more dynamic but didn't find anything compelling.
Anyway, they're now like new to match the monitor itself. To celebrate, here's a cursed video of it paired with a PowerMac 9600 playing a CD from 2020.
