First post, by RussD
So I'd been having trouble with my dual socket pentium pro motherboard and modern ATX power supplies. The 5V rail just sucked too much at powerup and caused the power supply over current protection to trip. There's three solutions to this, buy an older power supply that allows some droop an the 5V rail during startup, create an inline adapter for the supply that allows some droop on startup to limit inrush, or address the component causing the inrush. In my case it's was the VRM for the second processor. It has a huge amount of input and output capacitance.
I created a drop in replacement module using a modern regulator, the https://www.vishay.com/product/74589/. The resulting module is smaller, more accurate, has less ripple, is more efficient, and most importantly, has significantly less inrush current. It also allows a choice between the 5V rail and the 12V rail.
I'm currently stress testing the module as well as getting some good measurements on ripple, inrush, accuracy, etc. I added some jumpers to allow experimentation with overclocking. The jumpers allow the target voltage to be increased by 200mV, 100mV, 50mV, and 25mV allowing for an increase of up to 375mV in 25mV steps. I have 3 modules and I'm only keeping 1, so if anyone is interesting in the other 2 after testing is complete I can put them up somewhere. If there's further interest I can always make more. However, it doesn't appear as there will ever be a shortage of original VRMs available for cheap and this module does have the disadvantage of looking very out of place on a late 90's motherboard.
I've tested so far that it provides the right voltage and can provide up to 9A continuously. I'll update the thread later when I have some additional characterizations such as inrush, ripple, etc.