Thread: Machine tester

I bought this strange device at a swap meet for 5 bucks

It appears never used .

You place the tip against a machine and listen for noises A transistor amplifier and a 9 volt battery are inside the tube .

The instruction sheet has some funny English grammar , made in Japan it says . At a guess , early 1960's era. A pic shows a guy listening to a bench grinder with the device .

You beaut ultra modern electronic machine stethoscope. If a machine is making odd sounds somewhere but it is hard to localise the problem by other means, you can use a conventional acoustic stethoscope (like a medical one but generally with a smaller sounder, or a sounder with a fine probe), a long slender screwdriver held to the technicians ear, or a gadget like that, to probe around the faulty unit. While there will generally be a degree of the fault noise throughout the machine, it will be much more pronounced when the sounder/probe/screwdriver tip is located on the faulty component, typically one of a multitude of bearings in the machine.

Have also seen similar units used with engines etc where one cylinder is pinging and carbon build up around the head, valves, cylinder crown is suspected as a cause, or where there is one noisy tappet or faulty hydraulic lifter. Does not give a lot of useful info for a common straight 4 or 6 car engine, as lifting the head accesses all cylinders anyway, but once you get into V's, radials etc, it can be very handy to know which head to pop to approach a repair. The more heads to worry about, the more useful it becomes, particularly once you get to the 28 pot radial aircraft engines ( 4 rows of 7 cylinders back to back).

I haven't seen a unit exactly like yours, but have seen late 70's/early 80's equivalents in use on large factory machinery and in motor maintenance. Some business's with a lot of machinery to maintain would regularly monitor operating machinery with similar units as part of a preventative maintenance data collection system to get indications of pending failure to schedule downtime for repairs before the machine failed totally, thus minimising lost production and profit.