High and low power target levels must be calibrated across multiple frequency test points (typically 7 to 9 points across the band split).
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Check forward power with wattmeter → 0W ↓ Check PTT line: Pin 2 of accessory connector to ground when mic button pressed. ↓ Check PA enable signal (PA_EN from U101 to U401, pin 4) → Should be >2.5V during TX. ↓ Measure final transistor (Q401) drain voltage → Should be 13.8V during TX. | | Yes (0V) Yes (13.8V) Bad PA driver stage Check bias: R401 (adjust for 100mA idle) High and low power target levels must be