Recently I got a 0.9GHz 500mW video transmitter for repair. The owner just connected power reverse polarized and the transmitter went up in smoke. 🙄
I took the transmitter apart and after a quick voltage check I found the voltage regulator to be defective.
Just replaced the 78M08 linear voltage regulator on the lower side of the PCB, the part circled in red.
Took also some quick RF measurements to check the transmitter:
|DIP1||DIP2||TX Frequency||RF Power|
RF Harmonics for 910MHz, 27.44dBm TX:
1280MHz = -20.6 dBc
2730MHz = -14.8 dBc