The HP 3314A is a interesting 20MHz synthesized signal generator. I think it has remained popular because of its compact size and friendly front panel. It is much more appealing than button-happy bench hogs like the HP 3325A and Wavetek 178.
Click here for the HP 3314A specs from the 1983 HP test equipment catalog.
John Bump was nice enough to tell me about an Easter egg programmed into the HP 3314A by his father, Robert Bump:
My father designed the machine ... he programmed in a neato Easter egg. If you power it up while pushing 3 buttons, it'll play the Hallelujah Chorus in four-part harmony.
The HP 3314A easter egg, playing the Hallelujah Chorus, is in fact accomplished by hooking a 4 or 8 ohm speaker to the output, and pushing the blue (shift) key, the "SW/TR INTVL" key, and the "START FREQ" key. Hold all three down and turn the power on. You'll know immediately because rather than doing a CAL 999 888 777... it'll do a CAL AR1 AR2 AR3 and flash a bunch of numbers, then after about twenty seconds of digging around through setup stuff, it'll start playing its little song.
While the music is playing, the HP 3314A will display numbers mysteriously related to the note frequencies. The "ms" annunciator is on, but it doesn't seem to be displaying the waveform period.
NEW If your 3314A doesn't play the music properly, try resetting the ARB function registers. This fixed a problem that my own HP 3314A had, where the music would only play through the sync output, not the main output. Thanks to Federico Paoletti for figuring out this trick!
NEW Henry Ford of ETC Ltd. was nice enough to record the music to an MP3 file. Thanks Henry!