I recently had another Bose 901 Series I equalizer in for the standard repair service. It was from the later part of the Second Production run and so had a mixture of capacitor packages depending on the value.
It looks like the electrolytic capacitors were partially replaced somewhere along the way. The black capacitors had different lead terminations and were clearly hand-soldered versus the crimped factory component leads.
This equalizer got a complete overhaul with all new electrolytic and film capacitors and precision metal film resistors for low noise.
This equalizer will sound like new for many years to come. If you need yours fixed, too, I can help.