ebay board kits v 542 boards

[Jonathan]

thanks what range of va am i looking at. ie 300va 0-35 0-35

For 4 motors you want a minimum of 500VA.

So what happens when the onboard fuse goes or does that behave differently ?

That fuse is a much higher current rating than what you might expect (20 amps if I recall correctly). If it blows the driver is probably already gone so I bet it's more there to prevent fire.