Onkyo Rc-799m Remote Manual -

The tiny 8-pin microchip has lost its logic or a button is physically stuck. Fix: Remove batteries. Press every single button 10 times rapidly to unstick any mechanical jams. Wait 10 minutes. Reinsert batteries.

If you need the original PDF, search the official Onkyo support site under "Archived Products" or visit ManualsLib. Search for "TX-SR576" or "TX-SR606" – the remote manual is bundled with those receiver manuals. onkyo rc-799m remote manual