This board is ideal for pinball shows, temporary fixes or that last minute problem when a machine starts resetting and there is no time to fault find and repair the flaky 5V rail.
Homepin doesn't suggest that this board is a "fix" or repair for this type of resetting but it certainly can help both to get a machine running in minutes and also for faultfinding towards a complete repair.
No harm would come to the machine if this board is left in place, it's just good electronic practice to eventually fix the original cause of the poor 5V supply.
To install you simply unplug J210 on the MPU (with power turned off of course) and insert this board inline - replugging the J210 connector into the top of this board. That's it!
The Homepin version includes a small digital voltmeter so the end user can see at a glance, without reaching for multimeters, that the voltage supplied to the MPU is correct and stable.