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48-200 Transitone

48-200 Transitone; Philco, Philadelphia (ID = 353396) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353397) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353398) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353399) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353400) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353401) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353402) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 353403) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 946527) Radio
 
48-200 Transitone; Philco, Philadelphia (ID = 946528) Radio
48-200 Transitone; Philco, Philadelphia (ID = 2270727) Radio 48-200 Transitone; Philco, Philadelphia (ID = 2270729) Radio
48-200 Transitone; Philco, Philadelphia (ID = 2270726) Radio 48-200 Transitone; Philco, Philadelphia (ID = 2270731) Radio
48-200 Transitone; Philco, Philadelphia (ID = 51145) Radio 48-200 Transitone; Philco, Philadelphia (ID = 104610) Radio
48-200 Transitone; Philco, Philadelphia (ID = 104611) Radio 48-200 Transitone; Philco, Philadelphia (ID = 104612) Radio
48-200 Transitone; Philco, Philadelphia (ID = 104613) Radio 48-200 Transitone; Philco, Philadelphia (ID = 267178) Radio
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48-200 Transitone; Philco, Philadelphia (ID = 2270727) Radio
Philco, Philadelphia: 48-200 Transitone [Radio] ID = 2270727 1400x1049
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For model 48-200 Transitone, Philco, Philadelphia Stg. Batt. Co.; USA
 
Country:  United States of America (USA)
Manufacturer / Brand:  Philco, Philadelphia Stg. Batt. Co.; USA
Year: 1948 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 5: 7A8 14A7 14B6 50L6GT 35Y4
Main principle Superheterodyne (common); ZF/IF 455 kHz; 2 AF stage(s)
Tuned circuits 6 AM circuit(s)
Wave bands Broadcast only (MW).
Details
Power type and voltage AC/DC-set / 105 - 125 Volt
Loudspeaker Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil)
Power out
from Radiomuseum.org Model: 48-200 Transitone - Philco, Philadelphia Stg. Batt
Material Bakelite case
Shape Tablemodel, with any shape - general.
Notes Color=Walnut.
External source of data Ernst Erb
Source of data Collector's Guide to Antique Radios 4. Edition
Circuit diagram reference Rider's Perpetual, Volume 18 = 1949 and before
Mentioned in The Radio Collector's Directory and Price Guide 1921 - 1965
Literature/Schematics (1) Photofact Folder, Howard W. SAMS (Set 33, Folder 483-19)


All listed radios etc. from Philco, Philadelphia Stg. Batt. Co.; USA
Here you find 3745 models, 2123 with images and 3140 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.



 


Forum contributions about this model
Philco, Philadelphia: 48-200 Transitone
Threads: 1 | Posts: 3
Hits: 1978     Replies: 2
philco: Transitone; 48-200 tunes only one station
Steve Goodwin
09.Oct.12
  1

My 48-200 has had all caps and resistors replaced, all tubes swapped out, and a thorough cleaning. It will only tune one station in the 640kc area. Tuning elsewhere on the dial decreases volume, but the single station is still there. Any ideas? Thanks from a newbie!

Thomas Albrecht
10.Oct.12
  2

Hi Steve,

When a radio will tune only one station, a possible cause is a nonfunctioning oscillator.  The mixer (or "converter") stage of the radio produces the fixed IF frequency (455 kHz) by mixing the station and the variable oscillator frequencies.  "Mixing" means that the mixer generates the difference freqency.  If the oscillator is not functioning, then the mixer can't do anything except pass through the original RF frequency.  Snice the IF is tuned to 455 kHz, only signals near the bottom of the dial have any chance to get through, and usually this is only possible if the IF alignment is not proper.

An easy way to tell whether the oscillator is working is to measure the oscillator grid voltage.  In this radio, that is pin 4 (marked with a big "D" on the schematic) of the 7A8 converter tube.  This point should be at least a few volts negative compared to the cathode (pin 7).  You must use a high impedance voltmeter when making this measurement (any modern digital multimeter will work, or an older VTVM or FETVM, but not a cheap analog meter).  If you have an oscilloscope, you can also use it to check the signal on pin 4.  It should show the oscillator frequency, which is the dial frequency + 455 kHz (e.g., 1045 kHz if the dial is tuned to 600 kHz).

If you confirm that the oscillator is not working, check the "oscillator plate" (pin 3) voltage (which should be around 90 V) and the screen grid (pin 5) voltage (which should be around 45 volts).  Check R400.  Make sure the tuning capacitor plates in the oscillator section are not touching.  Check for continuity on both windings of the oscillator coil (proper resistances are shown on the schematic).

Best regards,

Tom

Steve Goodwin
12.Oct.12
  3

Thanks, Tom!

It took me awhile, but after fiddling with the oscillator section other stations finally spoke. Several voltages were low. Your assistance is very much appreciated!

Steve

 
Philco, Philadelphia: 48-200 Transitone
End of forum contributions about this model

  
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