All I have is the handwritten "221D024 Omron" on the FSM that I downloaded from Harman's site. Harman/Kardon part number is 4331-2024716. I can say that it has a 24V coil as I did measure the voltage when I cleaned it as I was hoping to find an equivalent. I was however not smart enough to snap a picture, although it wouldn't be very revealing as I don't have the cover for it (so no pinout diagram, although I could certainly derive that from the traces)
I can get more info later but will have to wait until I either a) fix the Sony I just picked up from GW or b) get my Sansui back from the spa as HK stack is currently serving bedroom duty and in the interest of domestic harmony I don't think I should take down the bedroom system unless something actually breaks