Keeping Otto Happy

Not our particular system 90,
but one I found
on the Internet

Long before the advent of personal computers, some smart people in the broadcast equipment business came up with a dumb computer (by today's standards) to run an automation system. A rack of reel to reel tape decks, 24 cart carousels to play commercials, and a couple of tape decks dedicated to the station ID or weather were all controlled by those dumb computers.

The station here had a Harris System 90 for KXEO and a Harris System 90 for KWWR. Keeping Otto (Auto) happy was close to a full time job before they were finally replaced. Each tape deck source had a source card in the System 90. A red LED on the front of the card indicated when that source was ON and there was a toggle switch on the card to play the source into an audition circuit. Stations had Program and Audition circuits. Program was the on air chain, audition was used for things like recording music or voice or "cueing/previewing" audio prior to going on the air with an audio source.

Each audio source used an EOM (end of message) tone to tell the automation to start the next audio source. For the 10 inch reels of music tapes, the EOM was a 25 hertz tone. For Carts (Cartridge Tapes) the EOM was a 150 hertz tone that was not supposed to be on the audio track. EOM tones were supposed to be inaudible, but if you listened on a good enough system, you could hear the 25 hertz rumble and the 150 hertz hum regularly. Not just our stations, but almost any automated station.

This is closer to actual size than the one below.
Some IC's were about an inch long, sone half an inch.

ICs have a wide (side) part of the leg,
and a very narrow (front) part of the leg.
The thin part has just a fraction of the
surface contact area as the wide part.

The Harris System 90 was a DUMB computer. And I mean that in the best possible way. (not really). Uninterruptible Power Supply? Don't think so - the station had a 12 volt car battery (like the one that starts your engine) tied to each system to save the memory if the power failed. But since this was a dumb computer, the power fail circuit usually didn't work.

And the Sytem 90 functioned with RAM, random access memory, which would dump if there was a power failure or static in the tower guy wires.

In the design of the System 90, some "genius" at Harris used IC sockets that said "Made in Brazil" that grabbed the integrated circuit chips on the short side of the leg, rather than the long or flat side of the leg. So a little corrosion would cause an IC to stop functioning properly. ICs and sockets produced corrosion naturally over time. Harris had a term for what you needed to do to the circuit boards - "massaging the sockets". That meant pulling each IC out of its socket and putting it back in to restore contact. On a large circuit board with 50+ ICs, your fingers certainly got a workout from massaging the sockets. Eventually massaging the sockets didn't work.

So when Otto "dumped" - either by storm or poor contact, the entire day of automation programming for each station would have to be manually entered at the respective System 90 terminal. The GM's son worked nights for a time and got pretty quick at reloading the programming - he could have both systems back up and running in under 45 minutes. It took the rest of the staff much longer to re-enter the automation programming. The system relied on EOCs and EOBs to keep things on track. (End of cluster - the area in memory for commercial and music tape deck events, and End of Block -the end of an hour of programming and the beginning of the next. There were 3 ring notebooks with format sheets to show which event numbers got EOCs and EOBs as well as the audio source to make it sound like a radio station. And we weren't called DJs back then, we were known around the station as "programmers".

There was a light switch in a back room that powered a neon sign on the east end of the station building that said "KXEO Your Neighbor of the Air". The sign was not functional when I started in 1978, but there was a note taped next to the power switch that said "Turn this on and DIE". Seems when the neon sign got flaky, it would cause the automation systems to get flaky - starting and airing multiple tape decks at random. So they had stopped using the sign by 1976.

The AM tower was just behind the studio building, and it was isolated from ground to allow the AM signal to radiate. There were insulators on the guy wires spaced every so often. That spacing was a function of the wavelength of the KXEO signal.to keep the guy wires from absorbing all of the AM signal. But during thunderstorms, static electricity jumped across almost all of the insulators creating a pop-pop-pop sound, and a pretty light show with every thunderstorm that rolled by. That static electricity also caused the automation systems to get flaky, requiring manually playing a 10 inch reel of tape on both the AM and FM until Otto was happy again. And the static electricity jumping across the insulators usually started just before it would rain. Once it started raining, the light show stopped.

So with both stations automated, it was possible to leave the main studio for extended time periods. Each System 90 had a printer that used 4" rolls of paper. An automation event that played properly would print in black. If a source failed for some reason, it would print in red and you'd have to make up the commercial manually.

I was told our facility was "state of the art" for broadcasting. Maybe not in some respects at the time, but it soon would be.

So it goes.