|Year: 1946||Type: Broadcast Receiver - or past WW2 Tuner|
|Valves / Tubes||6: 7C7 7A8 7B7 7C6 50L6GT 35Z5GT|
|Tuned circuits||7 AM circuit(s)|
|Wave bands||Broadcast only (MW).|
|Power type and voltage||AC/DC-set / 115 Volt|
|Loudspeaker||Electro Magnetic Dynamic LS (moving-coil with field excitation coil)|
|from Radiomuseum.org||Model: 46-421 - Philco, Philadelphia Stg. Batt|
|Shape||Tablemodel, low profile (big size).|
Elliptical speaker 4" × 6". Sams photofact folder 465-12 date 10-46 features the Philco models 46-421 and 46-421-1 as the same schematic.
|External source of data||Ernst Erb|
|Source of data||Collector's Guide to AR4.Ed.,Bunis, tube|
|Circuit diagram reference||Rider's Perpetual, Volume 19 = 1949 and before|
|Mentioned in||A flick of the switch 1930-1950|
|Literature/Schematics (1)||Photofact Folder, Howard W. SAMS (Folder 465-12 date 10-46)|
|Literature/Schematics (2)||Machine Age to J.Vol.2 Stein 97 (page 218.)|
|Literature/Schematics (3)||Philco Folder for 1946.|
All listed radios etc. from Philco, Philadelphia Stg. Batt. Co.; USA
Here you find 3262 models, 1836 with images and 2620 with schematics.
Hits: 943 Replies: 0philco: Make a new Special Inductive Capacitor - IF trap.
Paul E. Pinyot † 2013
How to make a Philco “Special” capacitor.
Philco uses a Special Capacitor that has an inductive series coil added. Philco also uses a special capacitor that has highly inductive qualities engineered in. It is designed to bypass IF to chassis ground. This Philco 46-421 uses one of these as C401. I had to fabricate a replacement. This is how I did it.
To build the coil:
To adjust the coil:
Adjust the o-scope to display the signal and set an amplitude reference point. The o-scope has a percentage graticule. I set the amplitude for 100%.
Then raised and lowered the frequency. Added or remove coil windings until the signal decreased on either side of 455kHz.
Checked the top end and bottom end frequency at 90% attenuation. Once satisfied with the response replace the sticky tape with heat shrink tubing.
I tried a UL rated safety capacitor with a smaller value but birdies (harmonic interference) appeared across the band. I remade the filter with the original capacitance of 0.2 uf and all the birdies were gone.
Other reference reading can be found on the “Philco Repair Bench” web site. It has a great functional description of Philco’s Special Capacitors.