Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
This is another Radio Service
Data Sheet that appeared in the May 1936 edition of Radio-Craft magazine. I post this schematic and functional
description of the Canadian Westinghouse Model 175 7-Tube Dual-Range Superhet 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.
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 May 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 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.
