AM radio IF amplifier - testing with a signal sweep generator on GE Sportmate P-860A.




























This radio is a germanium transistor radio with 4 HF and 3 AF transistors.
First transistor is the oscilator, second transistor is mixer.
The first IF transformer works in serial resonance, second and third one in parallel resonance.
The intermediate resonance frequency is 455 kHz.

I have detached the collector of mixer transistor and instead of it I have attached output from
a sinus sweep frequency generator 455 kHz. Signal strength is 100 mV peek-peek, sweep frequency is 100 Hz.
It sweeps from 445 to 465 kHz, it means interval of 20 kHz, 10 kHz under and 10 kHz over the IF.

GE P-860A radio

Sweep generator     Scope