Hi all, am having similar problems with my AC/DC premium. The flicker is so bad it's hard to play to be honest.
I've tried wobbling the lugs on the BR and this doesn't seem to have any affect.
I've tried unplugging and plugging back in all connectors and on the GI controller board.
What I've done for now is disable the under playfield GI and this has the effect of (a) stopping any flicker and (b) losing the hell section red GI underneath.
There are connectors for RGB extensions on the board (2 pin connectors) for the Red, Blue, White GI and the under table which are Red. They can be tested in the DIAG/ACDC/RGB Ext.
Note that if I disconnect any of the above, the flickering stops but obviously you lose the associated GI circuit. Of all these the under table GI is the least seen so I disconnected that (unplugged it).
All the GI circuits above work, and the flickering disappears if one of them is disconnected.
I've added a trough light to the game, this has no effect in the flicker whether connected or not.
So I believe I'm looking at a board fault or more likely a power/voltage problem as it seems to fail when all connected.
Could it be possible that the large capacitor on the board has failed 10000uf 16v?