Use Google to look at old discussions of this issue, but I *think* that
ver. 1.02 boards are incapable of supplying the required voltage.
-=-
Alan
On 06/23/03 10:19 am Matt put fingers to keyboard and launched the
following message into cyberspace:
I've been trying to fit a new cpu to
my aging p2b mobo, its a straight P2B rev 1.02
bios 1012 and the cpu is a P3-800/256/100/1.7V SL4BY
is there any compatibillity issue with such a combination ?
setting the jumper to 8x100 is unsucessfull, no Post at all
is there ather bios version than the 1012 that would fix the problem ?
is the 1.02 Rev to old for such a cpu ?
is there anybody out there ? ;p
This page has some revision information. I think it says the board has
to be revision 1.12 or later, to give a voltage less than 1.8 volts.
http://homepage.hispeed.ch/rscheidegger/p2b_procupgrade_faq.html
To make this work, you have to change the VID code. I modified a slocket
to do this. In your case, you need to change the VID1 signal from a
logic 1 to a logic 0. So, grounding the VID1 signal would tell the
voltage regulator on the motherboard to supply 1.8 volts, instead of
the 1.7 volts the module is asking for. (VID codes are open collector
logic, with pullup resistors on the motherboard making the logic 1,
and the processor shorts the signal to ground to make a logic 0.
So, where there is a VID code of 1, the processor is basically
not connected to that VID signal.)
VID4 VID3 VID2 VID1 VID0 Vcore_voltage
0 0 1 1 1 1.70
0 0 1 0 1 1.80
To understand what is happening, here are the datasheets for an old
and new voltage regulator (this was used on my motherboard).
http://www.intersil.com/data/FN/FN4/FN4417/FN4417.pdf (HIP6004A)
http://www.intersil.com/data/FN/FN4/FN4567/FN4567.pdf (HIP6004B)
On the 6004A regulator, when asked for 1.7 volts, it outputs 0.0 volts
and so the computer won't post. The lowest valid voltage setting on the
6004A is 1.8 volts, so that is why the VID code must be changed to
accomodate the missing settings.
[ Changing a 1.7 or 1.75 volt Coppermine processor to 1.8 volts is
safe, but doing this to a Tualatin is not recommended, as a Tualatin
is a 1.5 volt processor with a maximum Vcore allowed of 1.75 volts. ]
So, now all you need to find, is instructions for the best way to
implement the modification
HTH,
Paul