: Within this menu, settings like bfC , fr0 , and loC appear. Pioneers discovered that these control the BFO (Beat Frequency Oscillator) and varicap voltages, allowing for surgical-level alignment of SSB signals that might be slightly off-frequency.
Since you requested a "full paper" style breakdown regarding the updated service menu for the (and its variants like the CRT SS 7900 or Maverick MC-7900), I have compiled a comprehensive technical guide below. anytone at5555n ii service menu updated