Many users complain that the AT-5555N II sounds "flat" on AM from the factory. Here is how to carefully wake it up.

Have you accessed the service menu on your Anytone AT5555N II? Share your experiences, tips, and questions in the comments below!

"You gotta hit the service menu," Big Mike had said over the phone before the signal cut out. "But be careful, Elias. One wrong move in there and you turn that radio into a brick."

Ensure the transceiver is completely powered off via the volume/power knob.

: Adjusting power settings too high can damage the radio's finals or amplifiers. Common Adjustment Parameters

| Parameter | Function | Typical Range | When to Adjust | | :--- | :--- | :--- | :--- | | | Reference Frequency (PLL Master Clock) | 0 to 255 | Most common fix. Adjusts the master oscillator. | | PA-H | High Power AM/FM Bias | 0-255 | Sets final transistor bias for high power. | | PA-L | Low Power AM/FM Bias | 0-255 | Sets final transistor bias for low power. | | Pc-H | SSB High Power ALC Threshold | 0-255 | Limits peak envelope power on SSB. | | Pc-L | SSB Low Power ALC Threshold | 0-255 | Limits low power SSB. | | Mod | AM Modulation Depth Limit | 0-255 | Maximum AM percentage (Factory ~95%). | | S-1 through S-9 | S-Meter Calibration | Varies | Adjusts receive signal strength reading. |

"Come on," he coaxed. SA turned to -- .

: Adjusts the microphone audio width in FM mode. Standard calibration is typically set for a maximum of 2.5 kHz or 5.0 kHz deviation depending on regional bandwidth rules. 5. S-Meter Calibration (RX-S1 / RX-S9)

There is no "reset" for individual service menu values; once changed, they are overwritten.

Do you have access to external test equipment like a ?

Must provide a stable 13.8 Volts DC at a minimum of 10 Amps. Voltage drops during testing will cause inaccurate calibrations.

The service menu is a hidden interface used for internal alignments like frequency offsets and RF gain levels. Accessing it requires a specific key sequence during boot-up, and because there is no factory reset for these internal values, it is critical to record your original settings before making any changes. Accessing the Service Menu