Quoted from PinMonk:If you aren't comfortable or capable of working in or around a live power-supply, DON'T DO THIS. You can get shocked if you do dumb things like stick metal tools into the power supply leads.
Spike machines have a watchdog circuit that will cause the machine to reboot if the voltage drops below a certain level. It can affect all Spike machines through at least BM'66, maybe all of them. It usually happens when you're in a mode with a lot of action (lots of balls, coil hits, flashers, etc) that put too much load on the power supply output and cause it to drop momentarily low, which triggers the watchdog and resets the machine. You can fix this by bumping up the output from the power supply a maximum of 10% over stated spec.
There is a potentiometer at the bottom of the power supply (see picture) you turn VERY SLIGHTLY clockwise with a plastic tool to increase the power output. It's best to get a baseline with a multimeter, then use alligator clips so you can watch the output as you turn the potentiometer to get it where you want it. It will not take much to stop it from dipping low under load - much less than 1v. It's recommend only bumping it a couple tenths of a volt and see if that fixes your problem. If not, do another 0.2v increase and test again. It shouldn't take much to keep it stable even under load.Supposedly Stern has adjusted this watchdog circuit with software updates, but resets are still happening, so I don't know if it's not updated on all machines or if the software fix doesn't work well. The above change should help stop your resets.
Turning a pot is fine but you cant randomly do it without properly measuring the logic 5 volt line. If you adjust too high without measuring by a multimeter you can cause damage.
We do not recomend customers to make adjustments without being fully aware of the damage it may cause and even worse if the pot is damaged by putting pressure or adjusting with the incorrect tool or procedure.
