Difficult to know without design docs & part nos.
However, IR receivers typically have 3 pins (3.3V or 5V, GND, and output signal).
Your best bet is to get a multimeter and see if you can follow the traces on the PCB or see if there are any markings. If there are more than 3 wires in the cable connected to components on the PCB, then it is probably more complicated. (If there is an indicator red LED on the PCB, some TVs flash a red led to signal when IR is being received.).
The other way would be to de-solder the IR receiver.
IR receivers, typically are wired as follows (With the bulging lens facing you and the pins pointing down)
Left pin is Output signal
Middle pin is Vcc or
Right Pin is GND or
If you can identify GND (or Vcc) then there is a good chance you can figure out the rest, from the above.
Another clue could be that any capacitor is typically connected between Vcc & GND
I have often wired some IR receivers up the wrong way round, by accident, without damage after several minutes - but you may not be so lucky
Your only other option would be to upload good photos of both sides of the board.