William R. Walsh wrote:

Hello all...

I was cleaning up some stuff in the basement when I found a cardboard
box with a Newsweek address on it. Opening it revealed a small
white-cased device with an on-off pushbutton and a speaker. It uses 4
double-A batteries. There are no other controls or indicators on it
anywhere.

I first thought that it had to be some kind of a fixed-frequency
radio, probably something that was tuned to one AM station for
promotional purposes or maybe even a weather radio. But it doesn't
seem to receive anything--assuming it even works. With batteries in
place, it would hum (much like ground loop hum) and the sound would
get louder near electrical wiring. I never heard any sort of station
or static.

Taking it apart revealed a very simple circuit board with a coil,
power switch, a few small transistors, some resistors and a few caps.
It's really very simple--too simple to be any kind of radio I'd know
about. The one IC on it is an STMicroelectronics TBA820M audio
amplifier, with a date code of early 1988. Running it while taken
apart revealed a few things--let the circuit board get near the
battery compartment or wires, and the speaker would go into feedback.
The coil on the board was sensitive to touch or metal tools--and
produced a "tapping" sound in the speaker when touched. It was not
sensitve to other random objects on my workbench. I also found that I
could feed audio into one of the connections on the coil and hear it
clearly through the speaker.

A picture of the circuit board is he
http://greyghost.mooo.com/newsweek-radio.jpg (541x255, 47KB)

William

It could be an induction loop amplifier ! Used by people that are hard
of hearing !

--
Best Regards:
Baron.