Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
At least for now, I am going to
only scan and post schematics & parts lists like this one featuring the Kadette Jewel Model 40 Chassis 3-Tube
Ultra-Midget Receivers Model 41, 43, 44 and 48 radios in graphical format, rather than run OCR on them to separate
the textual content. 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. I will keep a running list of all data
sheets to facilitate a search.
The Kadette Jewel Model 40 Chassis 3-Tube Ultra-Midget Receivers Models 41, 43,
44 and 48 Radio Service Data Sheet
A.C.-D.C. operation; new type balanced-armature speaker; range, (Size, 5 1/2 x 7 1/2 x 3 3/4 ins.; molded bakelite
cases in many colors; 550 to L600 kc.)
The circuit of this receiver is of the A.C.D.C. type, the 12A7 tube, V3, acting as both rectifier and power
tube. Voltages are as follows:
These readings are taken with the volume control on full and no-signal input. All voltage readings except the
heater taken with a 1,000 ohms-per-volt meter, to chassis. The circuit is one of extreme simplicity (which accounts
for the long trouble-free performance to be had). The set runs quite cool due to the fact that the dropping resistor
is in the line cord. A magnetic speaker of new construction is employed and will give good service without the need
of any adjustments. The case is of solid molded bakelite and may be had in several different colors. The speaker
grilles are detachable and are also supplied in several finishes. The set is ideal for the traveler, since it is
so small, and a suede carrying case may be obtained for carrying and protection. Since V3 is a dual tube, the set
gives a performance equal to those using 4 tubes, resulting in very high sensitivity for a set of this type. To
test for alignment, insert a thin strip of mica, bakelite, or celluloid between the plates of the tuning condenser
sections. Tune in a signal then open the condenser slightly below the point of resonance. Insertion of the feeler
should now increase the signal, and as the feeler is pushed still farther between the plates, the signal should
drop off. Correction for incorrect adjustment is made by bending the plate sections at the point of mesh, checking
at 1,000 and 550 kc. The trimmer condensers should be set for best gain at 1,500 kc.
Posted August 27, 2015
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...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
