09-28-2024, 09:03 AM
Yes, 48 is a bypass cap always in place. Important because it also has a role in cutting down on parasitic oscillation. There may be a mistake in the value for #47. I think that it should be a 0.015 uF cap, not a 0.15uF. That would cut off too much treble with the tone control in the low position.
#4 on your pic is a 300 Ohm wirewound resistor that serves as the cathode bias resistor for the 44 RF and 44 IF tubes. There is a numbering mistake on the pictorial. The resistor should be labeled as #5.
According to the schematic, #5 is this 300 Ohm resistor and #4 is the multi-capacitor can. The cap that is shown as #4 on the schematic that parallels that resistor is listed as 0.09uF. A 0.1uf cap will do fine here. If the resistor is out of spec, a 300 Ohm1 Watt or 2 Watt resistor should do fine. I don't know why they used this type flexible wirewound resistor. It could be for space considerations or adding inductance because it was wirewound.
These multi-caps were an effort at streamlining assembly, as all of these caps are "bypass" caps, where one end connects to chassis ground and a wire for each individual cap goes to either a cathode resistor or a voltage divider that supplies a plate or screen voltage. These were easier to assemble and wire into the circuit than 5 individual caps. This was also the theory behind the bakelite blocks that Philco used. If one of these bypass caps was left out, oscillation or "motorboating (low freq oscillation) could occur.
BTW, the underside of the chassis, wiring, the tuner drum, etc. is in fantastic condition given its age. I have rarely seen coloring on cloth covered wire this nice on any set I own or have worked on, with the exception of a GE S-22A (RCA R7A), Ca 1931, that came from Utah, likely from a smoke free home.
#4 on your pic is a 300 Ohm wirewound resistor that serves as the cathode bias resistor for the 44 RF and 44 IF tubes. There is a numbering mistake on the pictorial. The resistor should be labeled as #5.
According to the schematic, #5 is this 300 Ohm resistor and #4 is the multi-capacitor can. The cap that is shown as #4 on the schematic that parallels that resistor is listed as 0.09uF. A 0.1uf cap will do fine here. If the resistor is out of spec, a 300 Ohm1 Watt or 2 Watt resistor should do fine. I don't know why they used this type flexible wirewound resistor. It could be for space considerations or adding inductance because it was wirewound.
These multi-caps were an effort at streamlining assembly, as all of these caps are "bypass" caps, where one end connects to chassis ground and a wire for each individual cap goes to either a cathode resistor or a voltage divider that supplies a plate or screen voltage. These were easier to assemble and wire into the circuit than 5 individual caps. This was also the theory behind the bakelite blocks that Philco used. If one of these bypass caps was left out, oscillation or "motorboating (low freq oscillation) could occur.
BTW, the underside of the chassis, wiring, the tuner drum, etc. is in fantastic condition given its age. I have rarely seen coloring on cloth covered wire this nice on any set I own or have worked on, with the exception of a GE S-22A (RCA R7A), Ca 1931, that came from Utah, likely from a smoke free home.
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Best Regards,
MrFixr55