I owe you for pushing me over the edge
I also have to thank you for all the info, I got the last one they had in stock.
Is your TV switched on before you start the 5508? If yes, switch the TV off and then see if the problem persists. The backlight control on most new TVs interfere with remote controls.
Hope this helps.
Keep an eye on that. Both my 80.2's started off with the remote not responding. They then went into switching and locking on inputs, totally freezing, etc...
Note: Taking the batteries out and even trying a different universal remote never helped with mine. Only unplugging the unit then doing a reset.