If the correct sequence is executed, the display will change, and you will have entered the hidden service menu (items often ranging from 1 to 59 or more).
Rotate the main Channel Selector knob to scroll through the different menu functions.
The standard menu (accessed via the MENU key) offers a wealth of safe customizations that cover almost all user needs, including:
Calibrates the Peak Envelope Power (PEP) limit for Upper and Lower Sidebands. 3. S-Meter Calibration (RX S1 / RX S9) anytone at-5555n ii service menu
If you’re unsure, find a local ham with an RF lab. One hour of guided calibration beats weeks of chasing mysterious problems.
) signal into the antenna jack to calibrate the software S-meter accurately. Critical Warnings and Best Practices
Technician Tip: While it is tempting to max these values out, pushing the final transistors past their rated limits will cause thermal runaway, heavy harmonic splatter, and premature hardware failure. Keep adjustments within a conservative margin. 3. Modulation and Deviation (MOD / DEV) If the correct sequence is executed, the display
Always let your radio sit powered on for at least 15 to 20 minutes before making service menu adjustments. Internal components shift characteristics slightly as they reach operating temperature.
“I used the Service Menu to bring my AT-5555N II back to life after a failed mod. Reset the PLL reference and SSB ALC—now it’s the best-sounding radio in my shack.” — Mike, K6MRC
Once inside the service menu, you rotate the channel selector knob to cycle through the available adjustment states. Pressing the channel knob or FUNC button typically selects the parameter for editing. ) signal into the antenna jack to calibrate
To enter the hidden service menu, use the following button combination: Turn the radio completely .
Performing a standard user-menu reset will not restore the service menu to factory defaults.
Stabilizes phase-locked loop (PLL) tracking across different bands.
What are you trying to fix? (e.g., off-frequency, low audio, wrong power output) Do you have test equipment like a dummy load or wattmeter ? What firmware version displays when your radio boots up?
Over time, crystal oscillators drift. This menu allows you to correct the master clock.