Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Here is the Radio Service Data Sheet for the Canadian Westinghouse Model 175,
7-Tube Dual-Range Superhet as it appeared in the May 1936 edition of Radio-Craft
magazine. This is in tabletop format and has a Bakelite cabinet rather than the
more common wood. Using a moldable material permitted a more stylish (in some people's
opinion), curvaceous shape with a high shine. Radios with Bakelite cabinets that
have been kept in a climate controlled, protected environment still look almost
new even nearly a century later (see example from the RadioAttic website). With
six vacuum tubes in the receiver circuit (the seventh is the power supply rectifier),
this radio likely has very good selectivity and audio quality. I post this schematic
and functional description manufacturers' publications for the benefit of hobbyists
and archivists who might be searching for such information either in a effort to
restore a radio to working condition, or to collect archival information.
Canadian Westinghouse Model 175, 7-Tube Dual-Range Superhet
(6 metal tubes; Air Pilot; tone-flow cabinet;
ranges 530-1720,5,500-18,000 kc.; tone compensation; manual tone control.)
This set is similar to the Canadian Westinghouse Model 275, except that only
2 bands are provided on the Model 175.
All the voltages are given on the trimmer layout drawing. The D.C. readings are
taken with respect to chassis. The R.F. line-up frequencies are 1,500 and 600 kc.
for band A; 17,000 kc. on band C. Range B on the model 275 is aligned at 5,160 kc.
The receiver is designed to allow the Service Man to make use of a tuning wand,
and this tool should be used before any alignment is attempted. The I.F. stage is
aligned at 460 kc. Before actual R.F. adjustments are started, the dial pointer
must be set at the correct position. This is done by turning the tuning condenser
to maximum, and setting one end of the pointer exactly to the horizontal line at
the low-frequency end of band A, while the other end should be within 1/64-in. of
the line at the high-frequency end.
The power consumption of these sets is 72 W., while there is 2 W. undistorted,
and 4 1/2 W. maximum output.
Westinghouse Model 175 Tabletop Radio Video
Automatic tone compensation is provided on the manual volume control, by means
of a resistance-capacity network, which increases the low-frequency response at
low-volume levels,
The Air-Pilot is a combination of features which are said to enable accurate
tuning of the receiver by even the most inexperienced owner. A world time map is
provided in an illuminated drawer. This is fitted in both console and table models.
The console receiver uses a 12 in. speaker, while an 8 in. unit is used in the
table model.
The variable condenser is mounted on a special shock-proof support, which prevents
microphonic howl due to acoustic feedback from the loudspeaker.
Posted February 13, 2023 (updated from original
post on 5/18/2015)
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 tying 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.
