Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
A fair number of these Philco Model 38-116; Code 125 radios are
still in existence and have been restored by collectors. I have been scanning and posting Radio Service
Data Sheets like this one featuring the Philco Model 38-116; Code 125 for many years now. It is very
unusual to have two full pages devoted to a single radio like here. There are still many people who
restore and service these vintage radios, and often it can be difficult or impossible to find schematics
and/or tuning information. A running list of all data sheets can be found at the bottom of the page
to facilitate a search.
Philco Model 38-116; Code 125
Radio-Frequency Circuit: 1. Connect the Signal Generator output cable to the "Red" and "Blk". terminals
on the aerial panel (rear of chassis). The ground connection of the cable should be connected to the
"Blk" terminal. Set the controls as given under "Intermediate-Frequency Circuit" (a-b-e-d) and set the
Range Switch, Signal Generator and Receiver Dials as given in the following procedure.
Magnetic Tuning Circuit Adjustment: (a) Set the Magnetic Tuning Switch in the "out" position (counter-clockwise).
(b) Volume Control maximum (extreme clockwise) . (c) Turn Treble-Selectivity control to the Selective
position (extreme clockwise). (d) Now turn the signal generator indicator to the 1,000·kc. mark and
adjust the "Attenuator" control for a weak signal. Then adjust the receiver dial for maximum output
at this frequency.
NOTE: The receiver dial MUST be tuned very accurately to the 1,000-kc. signal in order to make the
following adjustments correctly. (e) After adjusting the receiver dial, turn the Magnetic Tuning Switch
"on". (f) Now, turn compensator 53B slightly to the right or left (about 1/4 turn) and proceed with
adjustment "g". (g) Adjust compensator 53A primary of the discriminator transformer for minimum output;
then readjust compensator 53B secondary of discriminator transformer for maximum output.
Posted December 27, 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.
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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