Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
The
Brunswick Model 31 Combination Radio Panatrope was billed as the world's first all-electric
phonograph (as opposed to the mechanical crank-up models), combined with an AM radio.
It was designed with the assistance of RCA, many of whose components were integrated
into the unit. A video of a restored Panatrope is embedded on the page below the
data sheet. I couldn't find an official etymology for "panatrope," but the prefix
"pan" means "all-inclusive," and "trope" means "turning," like the turning of a
phrase. However, given that the Panatrope is a "turn"table, perhaps that was an
intentional distortion of the meaning to fit the device which it named, ergo, a
record player that had all available functions.That's my best shot at it. This Radio
Service Data Sheet for the Brunswick Model 31 Combination Radio and Panatrope appeared
in the February 1930 issue of Radio-Craft magazine. It includes
schematics and very detailed alignment instructions. A video of one in operation
is embedded below.
Brunswick Model 31 Combination Radio and Panatrope Radio
Service Data Sheet
In this receiver a radio-record switch, Sw2, cable and input transformer, T4,
are used, in order that the low-impedance of the pick-up may be matched with the
relatively high input impedance existing in the primary of T1.
Referring to the parts layout sketch, units TC1, TC2, TC3 and TC4 are trimmer
condensers in shunt to the tuning condensers but not shown in the schematic circuit.
This receiver is in three sections: The R.F. chassis, the "SPU" (socket-power-unit)
chassis and the dynamic reproducer. Field current for the latter is supplied by
the SPU. Note that operation of the receiver should not be attempted unless either
the field coil of a dynamic or a 600-ohm resistor is connected across the terminals
for the two "field" leads; this resistor must be capable of carrying 100 ma.
To facilitate service, the RF. chassis and SPU chassis are bolted to a single
mounting board which, in turn, may be removed from the cabinet by removing retaining
bolts at the rear of the mounting board which, in turn, may be removed from the
cabinet by removing retaining bolts at the rear of the mounting board.
For hum, two filament shunt resistors, R9, R10, with variable center taps, are
provided on the SPU chassis. R9 is adjusted first and then R10. If R10 appears unresponsive,
try other '27s at V4 and V5. Abnormal hum may be due to one or more of the following
causes...
Restored Brunswick Panatrope
Posted October 27, 2023 (updated from original
post on 6/9/2016)
Radio Service Data Sheets
These schematics, tuning instructions, and other data are reproduced from my
collection of vintage radio and electronics magazines. As back in the era, similar
schematic and service info was available for purchase from sources such as
SAMS Photofacts, but these printings
were a no-cost bonus for readers. There are 227 Radio Service Data Sheets as of
December 28, 2020.
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