On  7 Jan 99 at 7:31, John Chin wrote:

> Our college has received a donation of several older FX chipset
> P-54C motherboards (Zida 5DXP, to be precise) which are 3.3 volt
> boards with Voltage Regulator Module Connectors that require a
> daughter board to configure a different voltage.
>
> We have a Pentium 100-S 2.9 volt CPU which came without any such a
> VRM daughter board.
>
> Can anyone suggest a solution for setting the voltage for 2.9
> volts?  That is, a solution which would be cheaper than purchasing
> a new motherboard with manual voltage selection for this CPU?
>
> P.S. I have emailed Zida for assistance (who earlier provided me a
> manual, which only advised the use of a VRM daughter board) but I
> thought I would submit this inquiry to this diverse forum of
> hardware experts for alternative solutions.

  Many early (FX and VX) boards included a VRM socket -- it looks a
bit like an EIDE connector, but with one side "hinged", and if there
is no VRM installed there are probably jumpers across some of the
pins.
  Unfortunately, there doesn't seem to have been much standardization
of the pin assignments in these sockets; I was never able to locate a
VRM with any confidence that it would work in my VX board, and to try
to find one now is probably a lost cause.

  Your FX boards can still make usable Win 9x machines using P54C
CPUs such as P133, but I don't know where you'll find a 2.9v-capable
motherboard.  [Note that P55C "split voltage" can probably supply
2.9v to the core, but will still likely supply 3.3v to the I/O
circuitry -- and I gather that's not what this chip wants.]


David G

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