Photo Of The Month

As we continue to work our way through our archive of photos, we run across some that are a bit out of the ordinary. They may be humorous or unique but they stand out from the other photos. We post new photos here monthly with the previous photos in the slideshow.

The July Photo of the Month is from the October 26, 1972 issue of Electronic Design. The attention of the machine tool operator is directed at the familiar 611 Direct View Storage Tube (DVST) monitor. The 611 is incorporated into the 1791 Program Verifier, one product in a line of Machine Control or Computer Numeric Control (CNC) products started as part of a diversification effort in the late 1960s. These controllers were initially developed for internal use in the Model Shop. Tektronix units made use of TTL circuits (transistor-transistor-logic) while the commercial controllers of the day were larger, with vacuum-tube circuitry that was harder to maintain. The superiority of the Tektronix design prompted consideration of productization.

The first machine control units, the 1701 and 1702 were introduced in 1970. These were two-axis and three-axis controllers, respectively. There was subsequent expansion of the product line. The 1791 pictured on the Electronic Design cover was a dedicated program verifier, used to determine if the numeric control tape had been programmed with the correct machine-tool path. The accompanying article pointed out in conventional systems it was not uncommon for a new punch tape to be checked multiple times before it was confirmed to be ready for use. In addition to being time consuming, there was a chance mistaken programming could damage the machine tool by having it strike the work table or ruin the starting material.

The 1791 was one of the last products offered in the machine controller line, only appearing in the 1973 catalog. Several reasons are possible for the limited success of these apparently noteworthy products. Unfortunately, they were introduced at a time when the machine tool industry was in decline. Bill Walker was quoted as saying “It’s been like leaping into a pool just as they let the water out.” There were reports that Tektronix CNC line was in direct competition with companies who were important customers for other Tektronix products.

However, the controllers continued to be used widely in Tek’s machine shops for several years. More information is on our Machine Control page.