Excellent Harman Kardon 680i Twin Power stereo receiver — Polk Audio Forum
HARMAN KARDON HK680i DIGITAL QUARTS RECEIVER ORIGINAL TECHNICAL SERVICE MANUAL | eBay
Harmon Kardon hk 680i 1983 Silver | Reverb Finland
HK680i and EQ8 ——-Paid $9.99 each! Its usually $4.99 at our local goodwill today, but still i cant complain!! Everything works and sounds awesome. Did not do any cleaning or anything yet.
1982 Harman-Kardon Ask any Audiophile
Harman Kardon HK-680ii - Audio Asylum Trader
Harman kardon HK 680i Vintage receiver hi-end - audioweb
HARMAN KARDON HK680I 680I Service Manual *ORIGINAL* BOOK OR PDF-FREE SHIP | eBay
Harmon Kardon hk 680i 1983 Silver | Reverb
Harman Kardon, HK-680i Digital Synthesized Stereo Receiver -SOLD – Holt Hill Audio
Harman Kardon HK 680i Twin Power Digitally Quartz Locked Stereo Reciever | #364055125