VM202 stop sometimes

For an installation, I made 26 systems with a vm202 player that played a 3 minute mp3 file follow by 7 hours of silence (to avoid the repeat).
It gets tension from a 220v to 12v transfo of 1000 mA wich is also alimenting a 2*10W amplifer.
I use only one side of the output because it’s going into only one speaker.
I have a resistance and the 12 to 5 v adaptator between transfo and vm202.
This system is working 8 hours per day but have a serious problems : sometimes it stop while it is still alimented. It is not always the same stoping but in general 2 or 3 systems on 26 are stopping every day.
I was thinking on some overheat problems because the ones exposed to sun stoppe more often.
Does anybody would have any idea of the cause of this disfunction ? Or any advise to avoid this stopping ?
Thanks and excuse me for my approximate english

Ivan the frenchman

Can you provide a link to a schematic and pics of your hook-up?