TEAC remote control RC-1181 no LED switching.

[Dieselman]

Hi, first post, so Happy New year to you all.

I have a non functioning TEAC RC-1181 as a result of no IR-LED function due to the logic chip failing to provide a shunt to Gnd for the LED return.

The chip is being supplied with reliable +3v power, Gnd, Pgnd and oscillator inputs.  It also appears to register all 30 key inputs, noted by triggering the oscillator when a key is pressed.
The LED functions when manually triggered and inverse voltage pulses can be observed on Pgnd, but no shunt to REMout occurs, which leads me to believe the internal gate is functioning, but the output is not connected to Pin 19 of the chip.

I can't find any information regarding the remote control itself and the RC-1181, or equivalent are not available. 
Other remote controls are available, such as the RC-1182, which I also have and is physically identical, but the buttons have different functions.
RC-1181 is for the Receiver/Amp and has control for other devices as well, RC-1182 is for the Cd player only.

The logic chip is an ADAM22P20SP. 

I have attached the two datasheets I have found for the ADAM22P20S as one has more detail, but the other more clearly shows the chip pin-outs.

My question is really, does the ADAM22P20S(P) need basic programming, which I can't perform, or can I obtain another remote and swap the chip over...if so, I can't see how the remote has different functions for different models of remote.