Just putting this out there because I'd never had all the GI die at the same time on a modern Stern with LED lighting and wanted to put the solution here in case someone else runs across this to save them time.

The Metallica Premium I maintain on route lost all GI. It wasn't a fuse, but seemed to be oxidation on the power connector under the playfield where the LED control board in the middle of the PF underside is, or a loose connection. Removing and re-inserting the 2-wire red/black power cable next to the RJ-11 connector (phone-looking cable) on that under playfield board brought back the GI.

EDIT: This happened again, and removing and re-installing the 2-wire red/black power cable by itself brought the GI back again, so that's most-likely the only point of failure here.

It happened again on the one I maintain on route, so you'll probably need a longer-term solution. Likely I'll replace the connector that may be oxidized (but in less than a year??) and clean the two prongs it slides on to. I'm 98% sure it's a WPC era oxidation issue like you would see on the stressed GI connectors of WPC machines, but it's weird to see it on a LED board power lead that's 20+ years newer. I need to check the voltage to see how much they sending down that connector.

EDIT: Yes, the connector pin 1 was discolored (brown) and oxidized. This after only about 8 months! I didn't have my meter to check the voltage, but they must be sending quite a lot down that wire. Replaced the connector and all is good again.

So a little follow up on this. The connector on this was the insulation displacement type where you slide the wires down and it cuts into them, making contact. This connector is known by Stern to cause these issues and was SUPPOSED to be replaced at the factory in new builds with Trifurcon connectors, but they didn't do it, so this issue may crop up for others before long, especially on route or if they leave it on a long time at home.

Awesome. Glad it's still helping after all these years.

Did you replace the connector? Even if you clean the pins on the board it plugs on to the connector, the connector receptacles may be too oxidized to conduct power.

Did you check the connector that often causes this issue from too much power through a connector not rated for the load?

Repinned before or after the GI failed?

Is the displacement connector plastic yellowed or browned? If yes, you probably need a new displacement connector. If you have a multi meter you can also check to make sure that there is voltage arriving from that connector and it isn't a blown fuse in the backbox instead.

It's a part common to a lot of Stern pins so it wouldn't be under just Metallica, although given that this is a common failure point, maybe it should be.

You just want a 3 pin displacement connector from pinballlife.com. The only variable is if that's 18 or 22 gauge wire, because that's two different connectors. You don't want one that's too big for the wires or the wires might not stay put.