My Philishave's battery became weak after years of running. Operating time was reduced down to about les than  a minute. I bought a new quality rechargeable battery and replaced the old one inside. Rechargeable battery type: NiMh, 1.2V, AA.

For dismantling use a thin screwdriver or appropriate tool which is used for replacing mobile phone's screen. Be patient while dismantling and

. When reassembling pay attention to laying down the inner parts correctly in their positons in order to provide normal operating functionality.