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Page 3
Page 3
Large Table Models (greater than 12 inches across)
Large Table Models (greater than 12 inches across)
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Early Table or Mantel Radio
Early Table or Mantel Radio
United American Bosch 5A (1931)Compact 5 Tube TRF Radio (2- 551 RF Tubes, 224A Det/Amp Tube, 247 Power Amplifier and 280 Rectifier. Uses a 6 1/2 inch speaker. There was also an early production run using 3- 224A tubes for RF and Det/Amp. The other difference were component value changes and front end connections. The model shown here was and early version that I updated to the better performing late production.
Examples of Late 1930s Depression Table Radios
Examples of Late 1930s Depression Table Radios
Zenith 6S223 (1937) "The Big Black Dial"
BEFORE RESTORATION
Sonora (unknown model) 1936-37. Possibly made by Sentinel Radio or Travler.
BEFORE RESTORATION
Second Restoration July 2014- restuffed ppaer capacitors with new ones, checked over and replaced resistors and mica capacitors, removed frayed wires and replace them and realigned all bands for accuracy and optimum sensitivity.
Paper Capacitors were cleaned out and restuffed with new capacitors.
Removed frayed wires
Hand rubbed cabinet with fine steel wool and bee's wax.
The Zenith Big Black Dial Look
2018 INFO UPDATERadio is fully functional, aligned and parts were rechecked.After 1931 Sonora went into bankruptcy and tried to reorganized many times. From 1932-1939 Sonora was in name only and often they had other regional radio manufacturers such as Travler, Continental Radio and Sentinel Radio manufacture radios and put the Sonora brand name on them.After years of sitting on the shelf as an unknown model, I finally found that this particular set was probably made by Sentinel Radio Corporation in Evanston, IL. This model is electrically similar to the Sentinel 19A. The big clue was that both sets used a bias battery on the 75 detector-amplifier tube, 3 bands and a two gang tuning capacitor. However it uses an extra 42 tube instead of the 76 tube. The other possibility is Travler Radio in Chicago, IL. Travler 633 and 634 is also very similar electrically, having 3 bands, same tube compliment (6A7, 6D7, 75, 76, 42 and 80), but no bias battery.First restorationReplace all paper capacitors and electrolytics. Notice a Cornell Dubilier molded capacitor on the lower right. This restoration has to be over 10 years ago. I use to think these were great capacitors along with Sprague Black Beauty. Notice the bias battery in the center. I didn't know what to do here so I left it alone. The set worked fine.
Electrical Once Over- January 2018Went over all resistors and found several way out of tolerance, replace CDE molded capacitor, found a fix for the bias battery and realigned the IF to 465 KHz.LEFT Photo
How to fix "dog bone" resistors that are way out of tolerance. Just put a resistor in parallel.
Other modifications include adding an extra pilot dial lamp for the SW band. The original design used a single bulb onlylit half the scale. Another mod was a safety issue, if the plug was inserted one way the chassis and the AC ground became live with 120 VAC. Checked the wiring and. Pre 1960 sets often connected the switch to the AC return side so the white or neutral wire on the AC cord must go there as was the case with this set. I did installed a polarized plug to avoid future potential electrical hazard. The final mod was to install a 41 tube instead of the 42 tube. The set worked fine and placed less stress on the power transformer which got quite warm.
New bias battery installed. Used a watch battery. Notice the green covering to prevent shorting the battery.
SHOWCASE:
Final Work on Sonora Table Radio Model ???
Restoration of Cabinet:
BEFORE
AFTER
Night View:
Real Wooden Back Cover!
Real Wooden Back Cover!
I made a schematic of this radio including the chassis layout. If you have a schematic of this set or see errors in the schematic please email me. It will be deeply appreciated.
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