Musical Fidelity A1000 Humming Issue

I have a Musical Fidelity A1000 integrated amp which lately has hum (~120 Hz) leaking from its separate power supply unit through the speakers after about 10 minutes of operation. I wonder if anyone has encountered this issue before? Also, does anyone know of a good Musical Fidelity repair shop in the LA/San Diego area? Thanks.
Could be tube going bad..???
No, the MF A1000 is a transistor amp.
Under warranty?
No, it's a long discontinued integrated amp which is a classic. I'm actually thinking of sending in to the factory who currently is offering a fine tuning program for most of their products but am put off by the shipping costs.
Contact Rick can search his phone number on Audiogon...
I ahve a A1000, sent it off to j s audio repair ex musical fidelity service manager. Did a fantastic job on it, i also hed my power supply upgraded.
Where is j s audio repair located? I may need to get my Tri Vista SACD player worked on.