there have been a few issues with ballasts from some sets recently. Linked?
Paul, the internal 7.5A fuse thing happened to me, every time I put beams on, a few seconds later it would pop. Apparently it's something to do with Fraud ballsing up the manuals (there's a ****ing surprise!) If you swap the fuse out for a 20A IIRC, that fixes it. There are individual fuses/relays in the aux fuse box but the internal one acts more like a thermal overload type of thing.