experiment with a AND gate with one input 38KHz from Func GEN and other input you can supply10Hz signal to it using a 555 as astable .then try to wire a RED led on the collector path in series with the resistor.now as the Tx is on 38 and Rx you have TSOP1738,
the LED should change status when ever the 2nd pin is going high and low. this will be a crude test for checking the function of Rx
- BTW check the prog content of the PIC you will notice that the frequency is set to 40
try if you can change it to 38 then perhaps it can respond. however what is the point in changing TSOP1170-- is it non availability?