In the days of yore, before all that hi-tech transistorized technologies of this era, mankind had to rely upon analog signals for most of his electronic data needs (electronic data that had, of course, not existed until they were created by the supplanting of older technologies). Though these technologies were marvels in and of themselves, they also spawned a host of related systems and technologies to calibrate, check, and adjust them.
Meet the IBM Time System Signal Analyzer, Model B.
This guy was found at a flea market some years ago. Almost totally non-working, its cord had rotted, the contacts were frozen, and the tubes spent. Together with my grandfather, we cleaned, calibrated, repaired, and restored, found a supplier of tubes in the Czech Republic, and got it working again.
Well, all except the meter. D’Arsonval movements, being electromechanical, are prone to failure. Somewhere in this old fellow oxidation has built up, and despite a few quivers here and there, and limited success passing current through the meter to break down the resistance, he is dead.
But the bigger questions were what was this device? What does it do?
An answer appeared out of the blue one fine day: an old manual emerged from some business’ archive, much to my amazement.
Well, it certainly dated the device anyway.
As it turns out, this little analyzer was used with the old electronic attendance and timekeeping systems installed in factories, offices, and many other buildings during the pre-transistor era. A neat system, actually, that would automatically record when people punched in and out, and could send the signals through existing power lines.
The systems were used for a number of years, but quickly fell out of use when digital systems took their place. But thanks be to a lucky find in the archive, this forgotten transitional technology can still be analyzed and understood.