On Thu, 2005-01-13 at 16:23 -0600, Richard Smith wrote:
On Thu, 13 Jan 2005 14:59:08 -0700 (MST), Ronald G. Minnich rminnich@lanl.gov wrote:
On Thu, 13 Jan 2005, Svante Signell wrote:
I found the BIOS chip brand and version: Its a Winbond W290C020-90
a nice common safe part. Try hamilton-avnet or arrow. WARNING: when you call them, use the EXACT part #. Their databases are not able to do fuzzy logic.
http://www.digikey.com is your friend.
Well really almost any JDEC part 2MBits and larger will work. If you use a larger part you might have to ground the unused address lines if they left them floating on the pcb.
Thanks for the links. No luck with any of the links given, however. How to find a replacement part?
no idea on the FSB settings -- I think linuxbios always goes with the fastest :-)
The FSB is set via the clock chip. The clock chip we have is set via straps. I'm not sure what your commercial bios is doing but the 440bx is not rated for over 100Mhz. So those other settings are overclockings. And they will change the speed of your PCI bus as well.
I know about the 100MHz rating for 440BX. However, on the board you can select 66/100 MHz FSB and the BIOS supports the higher FSB speeds. Also the board has multiplier settings (3-5) x (66,100) MHz = 200-500 MHz for CPUs with changable clock multipliers. The board runs today with dual Celeron (Mendocino, 300MHz, before Intel disabled dual on Celerons) at 103/66*300MHz = 466MHz stably for many years now.
BTW: The memories I have installed are all PC133 parts.
I suspect your board has a small microcontroller on it with eeprom that sets the strap settings on boot and then de-asserts reset. That or it boots in 66Mhz and then sets the clock chip after that.
Anybody know what clock chip is on that board?
Where to look for that chip?
The board also has a system manager jumper: Selectable between the SuperIO chip (default) vs. the PIIX4E (southbridge). Wht is the meaning of this choice?
I have the board description in pdf-format available if someone is interested.