The Fine Things are Always Hand Made
I am trying to help a friend who is working on a Philharmonic AM FM model. There are two bleeder resistors shown on the schematic of the tuner chassis. One has +250V on one end and multiple taps. The other has 17V on one end and multiple taps. Both have one end grounded. One of them may be the R1 listed as being a 125 ohm 10W resistor. The other one does not appear to be listed anywhere. Have any of you measured the resistances of the sections of both resistors and their total end-to-end values?
In the set being worked on, the defective resistor is in the circuitry where one end is connected to +250VDC. This resistor has no continuity to any of its connections end-to-end or either end to any of the taps. My friend says that he is afraid to dig into the insulation of the resistor as it is so tough and brittle he is afraid that he will shatter it if he forces scraping or probing into the tap area. The way he described the part, it sounds as if the connections are depressed or sunken into the surface of the ceramic body in such a way as to defy attempts to expose wire, scrape clean and resolder (if it is indeed a wire-wound type as we suspect). He said that just looking at the part it appears it could be a 20Watt resistor.
Thanks for the clarification on those two resistors and the value of the Sensitivity control!
My friend is working on the AM-FM set. I am just trying to update the schematic for a LW-AM-SW set based on the schematic that was in the archives here. This is a separate effort from what my friend is doing. The strange thing is that this schematic was listed as being for an AM-FM set in the archives, but it is not.
I ran across another anomaly in this schematic. There is a resistor labeled R1, that is indicated to be inside the 4th. IF detector circuit and the parts list says it is a 125 ohm 10 watt resistor. I think that is another mistake as I see no way that a 6B8G would ever be able to sustain the current required to justify a 10 watt resistor. Perhaps that should have been labeled as R10?