HP-71B Auto on

[J-F Garnier]

Indeed, the HP-71B CPU wakes from deep sleep every 4.55 hours to update the real-time clock. This is normally transparent to the user.
But if there is an unhandled service request at this point, this may leave the HP-71B awake.

A possible source of unserviced requests is the HP-IL.
You didn't give much details about your confguration, but if you have a HP-IL module, then try RESET HPIL.

A INIT 1 may help too.

J-F

[Edit:]
More details and example of HP-IL unhandled service requests here.