Usually accessed by holding down a combination of keys (often Menu + Power ) or via special service software. Calibrations:
Independent reverse-engineering has identified the RF power amplifier transistor as an AFT05MS006N from NXP (originally 6W rated) paired with a final amplifier stage that pushes it to the 20W range. The final stage driver is identified as an HTL7G06S01 from WATECH. This information is vital if you are repairing a unit with a burnt final amplifier. qyt kt7900d service manual
The MCU and SoC run on low voltage. Check the outputs of the internal linear or buck voltage regulators. If the MCU is not receiving exactly 3.3V or 5V, the radio will remain completely dead. Symptom 2: No Transmit Power (TX Out is 0 Watts) Usually accessed by holding down a combination of