The diode on the coil is probably fried again.

Sometimes I've tested the diode, and it tests good, so then I only replace the driver and pre-driver transistors, all is well, start a game and a minute later, the coil is locked on again.

So now, the flaky diode has killed the driver transistor again.

The moment the game is powered up, the coil locks on, even before the MPU boots.

I'll check the driver chip 7402 and make sure it's not cooked.

The fix usually is to, all at once, replace the Diode on the coil 4004, the Pre-driver and Driver transistor.

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A bad (or missing) diode will kill your transistor instantly.

Sometimes a flaky diode will test good, but the first vibration from the coil being triggered will make it momentarily go open, killing the transistor.

Make sure the new diode's band faces the red wires.

In a busy schematic, up arrows are often shortcuts to power, down arrows are often shortcuts to ground

I hear ya, but our meters can't always test a transistor, they are only 90% right.

All at the same time, replace the coil diode 4004, the pre-driver 4401 and tip102 transistors. Do NOT apply power until all 3 items are replaced, or one will kill the other and you will keep feeding the cycle.

Put the board back in with new transistors (even if they old test good), put new diode on coil, band facing red wires(even if old diode tests good).