The magnets work in test, but the 2.5 A slow-blow fuse blows during multiball.

Guns N' Roses: magnets blow their 2.5 A fuse in multiball

Cause: Electrical noise from the other coils gives the clock input of the 74HCT273 on the magnet board a false pulse, latching the magnets on. This can also destroy the IRL540 MOSFETs.

Checks

• Test the IRL540 MOSFETs on the magnet board.

Fix

• Solder a 0.22 µF non-polarised capacitor across pins 10 (ground) and 11 (clock) of the 74HCT273 on the back of the board.
• Replace any damaged MOSFETs and the fuse.

Systems

• Data East/Sega CPU Version 3b

Games

• Guns N' Roses

Related tips

• Last Action Hero / Guns N' Roses: magnet dead or locked on
• Magnet driver MOSFETs on Last Action Hero and Guns N' Roses
• Whitestar flipper weak or dead after a MOSFET swap: fake part, test with TPL1
• Logic-level MOSFET equivalents: 12N10L, 20N10L, 22NE10L, IRL530, IRL540
• Spare MosFETs for the driver boards
• Guns N' Roses magnets dead or locking on
• Guns N' Roses with a shaker motor was probably built for Japan
• Guns N' Roses: CPU and display EPROM types and latest versions

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)