Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Whenever I post any of these Radio Data Sheets from vintage electronics magazines,
I attempt to find photos of actual units. Drawings are good, but actually seeing
a for-real example is the best option. This Admiral Model 6RT44-7B1 phonograph
appears on the Radio
Attic's Archive website. As mentioned previously, electronics service shops
relied heavily on these Radio Data Sheets that were printed in monthly magazines
like Radio-Craft,Radio News,
and Radio & Television News. The alternative was purchasing service
documentation from the manufacturer (often only available to factory-authorized
shops), from Sam's Photofacts, or some
other third-party supplier. Of course experience and intuitiveness could substitute
for documentation, but as many episodes of John T. Frye's series of "Mac's
Radio Service Shop" illustrates, quirky variations in circuits can really throw
a curve to the serviceman.
Radio Data Sheet 345 - Admiral Model 6RT44-7B1
1. Loop must be connected during alignment. Check the set screws that hold the
tuning drum to the shaft to see that they are tight and that the drum has not slipped
on the shaft. The correct position of the drum can be seen on the manufacturer's
stringing diagram.
2. In the closed position the stop on the rear of the dial drum must be against
the stop post.
3. With the gang wide open, all slugs should be 1 3/8 inches out of their coil
forms. If there is any serious deviation or if there has been any tampering, turn
the adjusting screws until this distance is correct.
4. Be sure both the set and the signal generator are thoroughly warmed up before
starting alignment.
5. Turn receiver Volume Control full on.
6. Use lowest output setting of signal generator that gives a satisfactory reading
on meter.
7. Proceed in sequence as outlined below.
If it becomes necessary to change a tuning slug proceed in the following manner:
Set the gang to its wide open position, unsolder arid remove the old slug. Set the
slug adjusting screw about half way down. Place the new slug in such a position
that 1 3/8 inches of its length is above the coil form. Solder it in this position,
making sure that it does not slip during the 'operation and that the slug wire is
straight. Proceed to realign the set as shown in the chart.
Posted April 6, 2020
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.
