First post, by RetroSpector78
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So I have this PT-2006 i430VX motherboard that came with a WinChip C6 200.
It appears that the jumpers on the board were configured for an Intel Pentium 200 MMX (see picture), using 2.8v core and 3.3v io.
However, the system did start with the WinChip but it was very unstable and even after setting the jumpers to 3.5v it either hanged or blue-screened on me.
So I decided to switch to an Intel Pentium 200 MMX, and set the jumpers to 2.8v core and 3.3v io (see picture)
It managed to boot once, but then it hanged in the windows98 desktop. Since then I haven't been able to boot it with the intel mmx. (no post, nothing on screen, no beeps).
The WinChip is still booting with this motherboard, but has serious stability issues.
Now on the board I saw 2 voltage regulators. I am assuming one for the IO and one or the cpu core.
I got the following measurements without a CPU :
- The EZ1084AC always outputs 3.3v (I guess this is the IO voltage).
- The EZ1083CT is setup as an adjustable voltage regulator, and depending on VR1 jumper outputs the correct cpu core voltage (2.5v, 2.8v, 2.9v, 3.3v, 3.5v)
- Both are getting a clean 5V signal as input.
So these readings seem to be correct, albeit without load, so I decided to do the measurements again with the CPU:
With the intel MMX CPU installed :
- The EZ1084AC always outputs 3.3v
- The EZ1083CT outputs 1.4v
- Both are getting a clean 5V signal as input.
1.4v is defintely too low, and would explain why the system does not start and the CPU doesn't "warm" up. However, why would it output only 1.4v
With the WinChip CPU installed :
- The EZ1084AC always outputs 3.3v (I guess this is the IO voltage).
- The EZ1083CT outputs 3.3v (regardless of the jumper settings)
- Both are getting a clean 5V signal as input.
Strange that it always outputs 3.3v and not taking into account the VR1 jumper settings (2.5v, 2.8v, 2.9v, 3.3v, 3.5v)
Any ideas ?