I bought a 1.2GHz cheap receiver of those who do not have microcontroller inside, just a knob to tune,expected to find the pll chip inside, Not so, the PLL chip was missing.
Watching the tuner module can be concluded that the type PLL was SP5055, thanks to an old rusty tuner could be drawn from it a SP5054 chip, very similar in its functions and pins to SP5055.
Knob is a 10K variable resistor,volts tune only 0 to 5V DC
The tuner module has a small plate with a FM demodulator chip implanted.
Purely analog base-band no microcontroller, no video amplifier chip(NE592),only transistor type smd, chip for subcarrier audio demodulator type MC3361 of Motorola.
This photo shows the implanted SP5054, replacing the original chip SP5055
The micro controller type 12F629, input port is a RC IR sensor for Sony protocol,for example if press keys: "1","2","9" and "6",the receiver frecuency is 1296MHz, other example: "0","9","2" and "8",the receiver frecuency is 928MHz
Universal Remote Control (from my Cable Magic TV) as Keypad for set frecuency of this cheap and Mod FPV Receiver
if set frecuency out range of PLL, then blink led 20 times try locked(re-send serial bits),automatic enter a new setting and LED continuos.