To amortize a single payment, enter the period number and press SHIFT, then AMORT. The HP 10bii displays the annunciator PER followed by the starting and ending payments that will be amortized.
Press [=] to see interest (INT). Press [=] again to see the principal (PRIN) and again to see the balance (BAL). Continue pressing [=] to cycle through interest, principal, and balance.
Press SHIFT, then AMORT again to move to the next set of periods. This auto-increment feature saves the keystrokes of entering the new starting and ending periods.
If store, recall, or any other calculations are performed during amortization, pressing [=] will no longer cycle through interest, principal, and balance. To resume amortization with the same set of periods, press RCL, SHIFT, then AMORT.