This Bose® 901 Series II Active Equalizer, #114658, just came through the shop for repair. It had stopped performing the proper equalizer functions, and so was time for an overhaul.
Inside, it looks like the smaller electrolytic capacitors were replaced, but the large ones were all original. The first filter had blown out its positive end, no wonder this wasn’t working well anymore!
Time for all new components:
After an overhaul, it’s back to working and sounding just like it should!