Carefulnessly read narrate book of battery,use commendatory adapter.
Research whether the electric appliance and the HP ProBook 6540b AC Adapter contact elements is whether clean, when necessity clean with the wet cloth mop, after dry loads according to the correct polar direction.
When non-adult custody, donít let the child replace the battery, compact battery like AAA should be placed at somewhere the child can't attain.
Don't mix up new and old batteries or put different model batteries together.
Don't try to make HP ProBook 6540b rebirth use of hotting up, charging,or other way.
Don't let battery short circuit.
Don't hot up HP ProBook 6540b AC adapter or loss it in water.
Don't strip adapter.
Electro-adapter should be cut switch after use.
Should take off laptop from HP ProBook 6540b AC Adapter when battery long time no use .