Fortunately I found a thread which I would link but I couldn’t find it again. Series 4 processor keypads have power, led 1 is on but keypad has no function, leds don’t turn on momentarily during button press. When I was about to give up looking I found a post that discussed the plug in power supply inside the processor enclosure that feeds the keypad links and if that is faulty you’ll get the exact symptoms I was seeing, power but not good enough to work. Luckily I had a few of these power supplies in stock, swapped it out and everything is back to normal. Now we can take our time and discuss upgrading or downgrading. The QS vs QSX debacle which equates to upgrade a little or upgrade everything is pretty much disconcerting and normally if you upgrade you want the latest and greatest but in this case the latest and greatest has no backwards compatibility with anything. I’ve been slowly eliminating everything AMX in this home and now I might have to take the same approach with everything Lutron. AMX failure to support resi, no hand held remotes, etc, forced me to migrate away from them and Lutron’s short sightedness on backwards compatibility might do the same for them. In both cases I think its a new generation of greedier pencil pushers and been counters driving the bad engineering architecture decisions.