I just replaced my 950 with a 990. I have a Xantec 2 zone hardwire IR distribution system. I had a hardwired Zone 1 on the Xantec to the IR input on the 950 using a 1/8" stereo cable -- that all worked fine.

I plugged that same cable into the IR1 input on the 990, but it doesn't seem to be working. Note that if I use an IR blaster to the front panel, it works fine.

When I get back to my home city, I'll swap the cable with a 1/8" mono to see if that helps.

Any other ideas?

The 990's IR input is different than the 950's - I ran into the same problem. A Xantech system will need a 794-10 interface module to use the rear IR input, or you can stick an IR emitter on it (which I did because the IR window location is hidden behind the entertainment center's door).