This is a complex amplifier and the flashing lights may well be a form of warning that something has failed.
If it really is 'stuck logic' then I note there is what appears to be a backup cap providing an AT (all time) supply. Discharging this fully via a resistor (amp unplugged) and then leaving it for a few hours may/may not help.
I suspect the trouble will be more deep seated than a quick reset though
I have left the amp turned off at the mains overnight but to no avail.previous to this happening the headphone jack socket was loose the plastic thread holding it into the front panel had sheared off and a new assembly was no longer available the socket still worked.
Leaving it off probably wouldn't discharge the cap... the whole idea of an all time supply is for the logic to remember what state it was in when last powered up. That is why you would have to discharge it manually.
Normally backup caps are special very high value devices (around 0.1 to 1 Farad), however I've seen ordinary large value caps (such as this 1000uF or microFarad) used before.
In my experience if the memory capacitor goes leaky, usually both electrically and physically, the uProcessor will not reset and latches up because the reset pulse does not work. Remove the capacitor and discharge the VCC or power the A207 off for at least 3 weeks. If it doesn't change you have a fault probably in the output stage dragging a supply down.