narcotic wrote on 2021-05-01, 15:00:
I found this schematic to create a homemade vrm, but it is not the same as my board, it is a single row of 10.
http://john.ccac.rwth-aachen.de:8000/misc/lacuna_vrm/
Turned up this page while looking for something else, then found this thread when seeing if anyone already posted about it. So bump for attention to this little design that may allow quick and dirty VRM adapters for many a motherboard.
It further appears that because it's a low voltage differential design that that chip or it's siblings might work for Pentium regulators for lower core voltages or split core. However it may limit the usable CPU to under 200Mhz due to power dissipation ability. So while you might get split core MMX working on a P133 motherboard, you might only be able to go as far as P166MMX. (Worth investigating also are eBay DC-DC regulator modules that might regulate to 2.8V nicely from 12V with good efficiency)
I have a PC330 machine with similar voltage reg header as OP and might in time get around to adapting this design to use with that one. However, I have several other boards I could be running DX4 class CPU on and not so many 3.3V CPUs, so I am not feeling personal urgency to go anywhere with it for that purpose at the moment. Besides DX2-66 machines gotta be DX2-66ing to keep the dream alive right? 🤣
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.