HP 17bII Owner's Manual page 226

4. Never remove two old batteries at the same time, in case memory
lost. Remove one of the two batteries once. Insert a new battery,
making sure that the positive sign (+) is facing outward.
Do not mutilate, puncture, or dispose of batteries in fire.
The batteries can burst or explode, releasing hazardous
chemicals.
Warning
5. Remove and insert the other battery as step 4. Make sure that the
positive sign (+) on each battery is facing outward.
6. Replace the battery compartment cover.
7. Press on.
Now turn the calculator back on. If it does not function, you might have
taken too long to change the batteries or inadvertently turned the
calculator on while the batteries were out. Remove the batteries again
and lightly press a coin against both battery contacts in the calculator
for a few seconds . Put the batteries back in and turn the calculator on.
You should see               .
226 A: Assistance, Batteries, Memory, and Service
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