Tektronix 7854 Oscilloscope

Tektronix 7854

This is the 'scope and repair that began the collection. This is a legendary and famously expensive instrument, and the first scope capable of 10 GHz bandwidth that I ever saw and used early in my career at Bell Labs. The last great analog scope, but endowed with plenty of digital power. See it doing TDR (time domain reflectometry) with the 10 GHz head to locate a fault in our Apollo Guidance Computer memory module. Clicking on the picture or the link below will take you right where the action with the Tek 7854 starts:


Find a good overview of the 7854 mainframe in the TekWiki:


And a link to all series 7000 plug-ins


The user manuals, service manuals and schematics documentation is here:

Manuals on plug-ins are here:


Mine had quit. Fan would not even turn on. Probably a power supply problem. Which would be a good thing, because the analog and even more the digital portions of it are quite daunting.

Aided by my modern oscilloscope, I was able to find the culprit in the switching power supply circuitry. A bad electrolytic capacitor. A classic failure mode of vintage equipment:

Rig a modern one in:

And lo and behold, it works again! Until the next capacitor lets go .