The three-tone NBC chimes as described by Bill Harris in his article A History of the NBC Chimes were found by Brian Wickham. The chimes were later restored, and returned to NBC for their use. The following is Brian's account of the history of the NBC chimes:
The history of the chimes is hazy, but it seems to me I read that they were in use by the General Electric station group that became the backbone of the original radio network.
The chimes are now used to herald "The Ticker" on NBC football games and have been doing so since sometime in the 1994 football season (possibly 1993, it's not something you write down and remember). The actual sound used is a recording of a restored "Electric Chimes Machine" that was found in the garbage at NBC in 1977. The machine, from about 1930, was rescued by a radio engineer and given to me, as I was known to have an interest in these things. It was later returned to NBC and restored by Radio Net Maintenance to good working order and even modified so that it gave a clean ring off.
If you listen to old radio show recordings you will notice that the chimes are always bitten off at the end. The reason for this is that the chimes were rung by an electrically turned drum with metal nibs on it (same as a music box) that pushed down tuned sounding springs and released them. The cycle finished and the amplifier cut off while the "C" spring was still ringing. All of the original machines installed in NBC control rooms sounded this way. Since the chimes were used as a systems cue for switching, everyone assumed that they sounded cut off because someone pulled the switch and cut the ring off to that leg of the net. It is possible that they were designed to cut off because the switch was to be made anyway. (If you look through your old "Radio Age" publications, from Augusta GA, you will find an article on the Electric Chimes.)
The recorded chimes from that machine were used on the NBC Radio Net from about 1979, until, I suppose, it was sold to Westwood. The machine itself was supposed to have been installed on the Executive floor at NBC so that visitors could just push a button and here the original chimes. I don't know what actually happened to them.
My understanding is that it was Dick Ebersol's idea to use the chimes at a low playback level to alert the viewers to the "Ticker" which gives the current scores in all games. I thought it was a lame idea but when I heard it on the air I had to admit that it sounded pretty good and that it worked as intended. Besides, it's nice to hear the original chimes on the air on a regular basis.