Hi,
On the 150,
Set switch to X mode.
Type date as MMDDYY
Press CH button.
Remember, the 150 has no time system, so you must set the date every day.
I've never seen a 220 before, so I will have to guess with this machine. Try the 290 method:
Turn key to PGM mode.
Type date as MMDDYY or DDMMYY depending upon your country.
Press SUBTOTAL
Hope this helps.
Mark, October 2008