First post, by 386SX
Hi,
today I saved an old Pentium Socket 7 mainboard having a damaged eeprom with the hotplug changing technique both eeprom were 5V ones using (risking) a good Asus super socket 7 mainboard and end up correctly flashing a Winbond with the correct bios for a 35-8332-01 mainboard. And now this board is working again perfectly. 😀
But.. I have to try the same thing for flashing a 486PCI SIS496 based one using an eeprom MX27C1000-15 that need the VPP 12,75v for flashing. In the past I remember bending the pin using the +12 of the PSU to flash a similar way and it did worked if I remember correctly, but not in this case. I use the above saved mainboard and switching the eeprom with the latest pin outside the socket and applying the +12v and launching Uniflash or Ami flasher but both doesn't recognize the eeprom while suggesting it may be write protected. In the original bios of the Pentium there're no write protection, but on the mainboard there're jumpers for Intel/Atmel/Others eeprom and +5/+12v selection. I left +5v cause I suspect it refers to the VCC first pin and not the latest... is this correct? Or I need to set it to +12?
Or it may be the mainboard simply doesn't recognize it and have to try on another mobo?
Any suggestion how to flash this eeprom without external tool? With its own mobo there's no way already tried, no boot at all.
Thanks