I have a MSI MS-6147 Rev. 1.1 i440BX mATX board with no C letter on the Winbond I/O controller and have used a Pentium III 500@560 (112 FSB) Katmai for the last years. It has the SC1152CSW voltage controller, a newer version of the SC1152CS. Never thought, that this controller also supports <1.8V Vcore for Coppermines, the SC1153CSW supports VRM 8.4. MSI boards with the C letter on the I/O chip have the right SC1153CSW controller for official Coppermine support. So I have never tested a Coppermine on this board. For security reasons,...
But today I have tried it out on my MSI-6147: A Pentium III 700 1.65V Slot 1 Coppermine cB0 stepping (tested stable on a Abit BH6 board with 133MHz FSB=933MHz with default 1.65V VCore) installed, 500 Katmai out, and after the first switch on the Bios says: Pentium III MMX CPU at 784MHz, because 112MHz FSB was set in the bios. Tried Unreal, 3DMark2000, Incoming (Voodoo3 3000 PCI because no AGP slot) for the first time and everything works fine, also much cooler and less power consumption than the Katmai PIII clocked to 560MHz.
So the SC1152CSW is inofficialy able to handle below 1.8V. With the wrong not supporting <1.8V controller, you would get a black screen, because the needed voltage for the CPU cannot be provided and thus the controller interrupts the power supply of the CPU. Only a pin mod or a Slotket S370 with the voltage setting to 1.8V would help.