I agree, please remember the Voodoo402 4200 PCI 16MB and 32 MB are prototypes in some motherboards they may not function properly!!!
Like what happened with my Voodoo5 5000 AGP, it didn't function in the EPoX EP-8K5A2 Rev 1.1 it gave Black Screens as well in 98SE, 2KProSP4 and XPProSP2, but on the ASUS A7V333-R Rev.1.02 it worked perfect in 98SE with 2D and 3D and in 2KProSP4 and XPProSP2 it worked perfect in 2D but only single Chip in 3D , in dual chip SLi I also got the Black screen.
So what you are experiencing maybe Pure Prototype Flaws, it may work in a total different enviroment by meaning another Motherboard, Do not try changing the cards design by adding Capacitors that may destroy it.
Prototypes have the capabillity to succeed or fail, that's what makes them prototypes.