Preflashed BIOS Chips
Toshiba Equium L40-PSL49E BIOS Repair Notes
The laptop uses a 48 Pin TSOP part, the laptop we had in used the Macronix MX29LV800CTTC-70.
The EEPROM is located adjacent to the CPU socket and Memory slots on the Bottom of the Mainboard.
I had to make Brass heat shields to shield both the memory and the CPU Socket from the hot air flow whilst removing the EEPROM.
Don't know why as yet possibly age, but the solder required an extreme temperature to allow lifting the eeprom normally 350 to 450 degrees C, is enough to lift these parts. However I eventually moved up to 500 degrees which allowed me to lift the EEPROM from the board.
The solder left on the pads would not re flow even with repeated attempts to do so. I had to clean up carefully with an iron and solder wick before i could reposition the EEPROM on the footprint pads.
As most of the solder was removed during the clean up operation a fine tipped ESD safe soldering iron was then used to refit the EEPROM.
Even with the use of heat shields the CPU Socket still showed slight signs of cosmetic heat damage. However on reassembly the Laptop booted fine.
500 Degrees is a bit extreme for these parts and if used for too long it will damage the casing of the device and possible the device itself. Excessive heating will destroy the device so higher temperatures should only be used for a small period when need be.