BC-348-P Shortwave Receiver

Stromberg Carlson #2399

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I'm a hobbyist whose early years in grade school were often spent in the school library with the tattered copy of Alfred Powell Morgan's "The Boy's First Book of Radio and Electronics." Later in my teens I got into vacuum tubes projects.

Sometime in the mid 60's, Mihkel Schonberg, grandfather, inventor 1, inventor 2, employee (Jan 1958), et. al., gave me a BC-348 shortwave radio. Grampa would drive me to ACME Electronics Liquidators in Minneapolis when we visited. As a teenager I spent many hours listening to shortwave broadcasts. However, within a few years it developed RF difficulties and I was unable to repair it, mostly because I didn't have a schematic. Later in life I was able to repair and tune it up.

To bring back memories, there's nothing quite like turning the BC-348 on, letting it warm up for a half hour, then opening it up and sensing the smell of hot aluminum, oil, and old electronic components!

  Front view
  Inside top view
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Putting it in working order was easy when I obtained an original technical manual. It involved cleaning up some wiring, rebuilding a retrofitted preamp chassis, and replacing eighteen 0.01uF 600V caps (some of which were shorted.)

  BC-348-P retrofitted 8-ohm audio output schematic
  BC-348-P retrofitted 110VAC power supply schematic
  Power supply and amplifier

The P-version schematic is difficult to find on the web. Here it is.

  BC-348-P original schematic