Batteries - HP -28S Manual

Q:
I evaluated a variable or an expression, and now the calculator doesn't
respond. Pressing
I
ON
I
has no effect. What happened?
A: You defined a variable in terms of itself, creating a circular defini-
tion, and now the calculator is executing an uendless loop." To
terminate the loop, perform a System Halt as follows:
1. Press and hold 1
ON
I.
2. Press [!].
3. Release 1
ON
I.
Then redefine the variable to remove the circular definition.
If you don't find an answer to your question, you can contact our
Calculator Technical Support department, using the address or phone
number listed on the inside back cover.
Batteries
The HP-28S is powered by three alkaline batteries. A fresh set of bat-
teries typically will provide approximately six months to one year of
use. However, expected battery life depends on how the calculator is
used.
Use only fresh N-cell alkaline batteries. Do not use rechargeable
batteries.
Low Power Indicator
When the low battery annunciator (c:::::J) comes on, the HP-28S can
continue operating for at least 10 hours. If the calculator is turned off
when the annunciator first comes on, Continuous Memory will be
preserved for approximately one month.
286 A: Assistance, Batteries, and Service