For those who've never seen one, this is a piece of test equipment known as an oscilloscope. They are used to display electrical signals on a CRT and were once extensively used for computer repair back in the days where individual components were replaced rather than PC boards or entire assemblies.
One of the most versatile weapons in an engineer's arsenal, the 'scope allowed the measurement of voltage, time, and frequency (all at the same time). It is also possible to measure current in conductors using special probes. These features make 'scopes invaluable in the troubleshooting of complex electronic systems.
There are no transistors or ICs in this machine; it's completely implemented with vacuum tubes, and although it has a carrying- handle (2, actually) it can't really be considered portable. About the only place you'll see a machine like this is either in a museum or in an old science fiction movie (in which role they were popular props). This machine bears serial number 23454.
The functionality of this device rivals solid- state machines of a decade later and sports functions such as dual trace, dual sweep frequencies, delayed sweep with highlight, and contains a built- in calibration source.
The horizontal deflection functions, sweep, sync, and delay are built into the main frame; vertical functions originate in a plug- in module that can be changed as functionality requires. I have only the dual- trace plug- in module, which operates by either alternating sweeps for the two channels, or rapidly "chopping" them for simultaneous display.
This device is one of the oldest pieces in my collection and may possibly
be older than its owner. The 545A is fully functional (at least it was the
last time I powered it up) and when stuff breaks, I use it in the repair
process. It's an odd feeling using a machine that may be older than yourself
to fix a system you acquired a week ago!