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J-Mark (JetWay?) J-630BF missing BIOS chip
Posted: Sun Nov 26, 2006 9:14 pm
by trilioni
I have one motherboard that has an BIOS chip completely missing. Can someone tell me what kind of a chip should i use, or what kind of chip the mobo came with? Found the image of the bios that has the size of 256kb so i guess it is 2MB FLASH chip. Am i right? Is there any pin difference between various chips? Can something like this be used on this motherboard? >>
2MB Chip from Jameco
Any info would be of great help
Posted: Sun Nov 26, 2006 11:41 pm
by cp
take a look at this:
http://www.futurlec.com/Datasheet/Memory/AT29C020.pdf
and measure the voltages. there are mainboards that use 12V flash eeproms, too. btw. size calculated correctly :)
Posted: Mon Nov 27, 2006 3:03 pm
by trilioni
Does the motherboard get any power on BIOS chip pins without any CPU or add-on card installed? Or do i have to measure V with cpu in the socket and memory in the slots?
One more thing, can i use EPROM instead? (27c020) I assume the only differnece in pinounts is pin 1 which is Vpp - Program Supply in EPROM and not connected on flash.
Posted: Mon Nov 27, 2006 10:52 pm
by cp
voltages are on the chip as soon as you power up the board. no need to plug in anything else.
you can use an eprom, too. you can even build an adaptor if the pinout is different. just make sure the address, data and power pins are connected (and the device is selected (_CE) and outputs are enabled (_OE)).