There’s an unknown piece of armed forces electronic gear being investigated over on [Usagi Electric]’s YouTube channel (see video below the break). The few markings as well as labels on the box aren’t extremely helpful, however together with the building as well as parts, seem to determine it as relating to the us Navy from the WWII era. Its central function is a seeing-eye tube as well as an modification knob. [David] does a bit of reverse engineering on the circuit, as well as is able to fire it up as well as get it working, magic eye squinting as well as all.
But there’s still the unanswered question, what was this thing meant to do? Besides power, it only has one input signal. There are no outputs, except the “data” presented visually by the magic eye tube. Commenters have suggested it was utilized with sonar equipment, calibration tool, RTTY tuning aid, light exposure meter, etc. however if you dust off your copy of Navships 900,017 “Radar Systems Fundamentals” from 1944 as well as turn to page 249, there’s a section entitled tuning indicator that explains this circuit, almost.
This suggests these magic eyes were just being utilized as a sensitive voltmeter considering that they were much less costly than a mechanical meter. even if this is the function of the box, there is still the secret of what it was tuning. Share your thoughts on this in the comments below, particularly if you have seen one in the wild.