Mike -
I also have amps in the 500's that need repair. I am told that the following company does amp repair. You may want to contact them. ( Chicago area)
Midwest Audio
774 W. Algonquin Road
Arlington Heights, IL. 60005
phone: 847-640-1890
Good Luck
I also have amps in the 500's that need repair. I am told that the following company does amp repair. You may want to contact them. ( Chicago area)
Midwest Audio
774 W. Algonquin Road
Arlington Heights, IL. 60005
phone: 847-640-1890
Good Luck