Tektronix Programmer Manual 070-8318-04, TDS Family, Includes TDS 420, 460, 520, 540, 620 and 640. Digitizing Oscilloscopes. This manual supports the following firmware: TDS 420 & 460, TDS 520 & 540, TDS 620 & 640. First Printing August 1992. Comes from working environment, may have writing in and/or on it may have torn pages. This was used in CD lab and shows signs of usage. Please purchase accordingly.