I've owned maybe a dozen vintage receivers over the past several years, but this one remains my favorite (hence why I've kept it). I bought it on Kijiji for $80 a couple years ago and have since given it a thorough cleaning. I've also replaced all of the internal lamps as several were burned out.
Made in 1975 and the little brother to the HK 730, it features a "twin powered" design, which means each audio channel has it's own individual power supply. Even though it's rated at only 25 watts RMS per channel, it has more than enough power to fill a room. I'm currently using it as the primary receiver for my turntable and to power my floor speakers—I'll write about those another time.
Replacing the lamps behind the tuner dial was ridiculously easy. The hardest part was actually finding suitable replacements (more on that later). The lamps themselves are a fuse type, which don't require any soldering to replace; just remove the old ones and snap in the replacements. You just need to remove a few screws to gain access first.
I also had to replace the tuner needle light, which you can kind of see in the blurry foreground in the above photo (I don't know why didn't I take a better photo while I had it all dismantled). You just have to pry up the two metal side flaps and lift the casing off. Once removed, snip the wires to the lamp and solder the new one in place.
I ended up buying the lamps from this site, which was the only one I could find that had both the tuner dial fuse lamps and the tuner needle lamp in stock. The tuner dial lamps were part number L-11 (0.25" diameter, 1.25" long, rated 6V and 250mA), and the tuner needle lamp was part number L-5 (0.12" or 3mm diameter, rated 6V and 35mA). You can also buy the fuse lamps from Amazon.
Looking basically good as new! The next bit of repairs I might eventually tackle is replacing all of the capacitors with modern equivalents. There is an ever so slight hiss noticible when listening with headphones, and new capacitors might clean that up a bit—or so I've been told—as the originals are probably quite dry after 35+ years! I just need to practice my soldering skills first.