The tubes for the AM radio is the 12BE6 and 12BA6(above), the 2nd tube connects to the 2nd IFT then the diode. Take note, the positive end of the diode goes to ground which means the other side of the IFT is negative. Trace it to the 1.5M resistor to the secondary of the 1st IFT which feeds it to he grid if the BA6. Strong signals intoduce the negative bias to the tube. The audio is picked up from the same line via a 150k resistor which is tempered by a 4.5k resistor to ground.
In Japanese consoles, they use only the BE6 and the BA7 for te radio.No need for the detector tube. They just use a germanium diode, 1n34.
ReplyDeleteThe tubes for the AM radio is the 12BE6 and 12BA6(above), the 2nd tube connects to the 2nd IFT then the diode. Take note, the positive end of the diode goes to ground which means the other side of the IFT is negative. Trace it to the 1.5M resistor to the secondary of the 1st IFT which feeds it to he grid if the BA6. Strong signals intoduce the negative bias to the tube. The audio is picked up from the same line via a 150k resistor which is tempered by a 4.5k resistor to ground.
ReplyDeleteThat line is the AGC of the radio which is also connected to the antenna coil which goes to the side of the BE6.
ReplyDelete