The symptom was first seen just after a lightening strike where the laptop was disconnected from the mains however it was connected to an ADSL modem which in turn was connected to a PSTN telephone line. This could have been the source of the Voltage spike that could have damaged the laptop.
This article relates to the dis-assembly procedure of a Sony PSP-1004 model. First and foremost it is important to remove the battery and any slot in memory cards that are present. Remove also any Game in the drive.
