Fender Rumble Series 100/210 100watt 2x10 Bass Combo Amplifier "dimmer switch humming" Questions

I have a Focusrite Pro 10 i/o Firewire Interface and am experiencing 60 Hz hum through the mic pres when phantom power is switched on with the power supply attached. Phantom power running from 6-pin ...

...on longer and somewhat dimmer after this happens and after i throw the switch off. Other than that, it works fine. Any ideas? PLEASE? Replace C21 (10uF/50V) and C38 (2.2uF/50V) and it will work

...dimmer after this happens and after i throw the switch off. Other than that, it works fine. Any ideas? PLEASE? I just fixed my bass amp with a similar problem last week: the problem is related to a ...