Setting correct date

SOURCE: set date

To set the date Step by step as follows: Set the lever to "RATE SET", Press the clock/calendar key once and the date will be diplayed, key in the info as follows: 1/1/08 would be keyed in as "1" "." "1" "." "2008", the display will show 1.1-2008 then press the clock/calendar key, the correct date will show up.

To set the time Step by step as follows: Set the lever to "RATE SET", Press the clock/calendar key twice and the time will be diplayed, key in the info as follows: 12:00pm would be keyed in as "12". "00", the display will show 12.00 then press the clock/calendar key, the correct date will show up. For 12:00am key in "0",".","00" as it expects to see 24hr time.

SOURCE: EL 1801V - how to set time/date?

To change the date, enter the date in MM.DD.YY format, pressing the decimal key between the month and day (will show as a decimal on the display) and the day and year (will show as a dash on the display). Then, press the Time/Date key (the one that looks like a clock and a calendar). The new date will show on the display. Note that if the month is less than 10, you do need to press the 0 (zero) key for the first digit, even though it will not show on the display. To change the time, enter the time in 24-hour HH.MM format, pressing the decimal key between the hour and minute. Then, press the Time/Date key. The new time will show on the display. Note that if the hour is less than 10, you do need to press the 0 (zero) key for the first digit, even though it will not show on the display. Hope this helps! :)

SOURCE: need to change the time on calculator

To set up date, time, conversion rate, and tax/discount
rate, place the switch at the "RATE SET" position.
Date:
• Enter in the order of month, day and year, then press date/time button
to complete the entry.
• Use ▪ to separate month, day, and year EXAMPLE 3▪13▪2009.
• When (date/time) button is pressed, the number entered is evaluated
and displayed as “date”
Time:
• Enter in the order of hour, minutes, then press date/time button to
complete the entry.
(There is no entry available for the seconds value. The
clock starts at zero second.)
• Use ▪ to separate hour and minute values EXAMPLE 8▪15
• When is date/time button is pressed, the number entered is evaluated
and displayed as “time

When settings are complete place the switch back to GT

SOURCE: Sharp EL-1801P III Calculator Setting Time & Date

1. Switch the GT*RATE SET button to RATE SET.
2. Press the date/clock button to display current time.
3. Enter time wanted using military time. 4:52 p.m would be entered as 16.52 (Note the 16 is followed by . then enter the 52. (ie. 10:45 a.m. would be entered as 10.45)
4. Press the date/clock button again to enter new time.

Just reset mine and is current. If the built in battery needs changed, access panel is on the back. It uses a watch type battery.
~DLS

SOURCE: how to set date and time on sharp el-1801pIII

User guide is here ...

http://safemanuals.com/user-guide-instructions-owner-manual/SHARP/EL-1801PIII-_E

Instructions are halfway down column 1.
Basically, you use the reset button on the back, then enter the relevant fields, delimiting as with a period <.>

I think their illustration explains it better than I can in words!