So it works for a while and then the 7406 fails after a period of time? Replace the 7406 and it works again for a while until it fails?

If so id triple check that entire drive wire under the PF. It might be shorting to GI or something that takes a while for it it to fail.

You can close switches right at the connector plugs too with PF disconnected. That can help isolate driver board or PF.

7406 failures are almost always caused by a switch shorting to something. So yes i would thoroughly inspect the problem wire from the backbox to the playfield.

This most likely won't have any effect/help with your problem but I remember watching a TNT video on YouTube and Todd said Williams issued a bulletin to remove the top left and right screws from the driverboard as it can/may short the board to the metal bracket under it if tightened all the way.

My Firepower 2 has a burnt pop bumper coil, the right kicker is stuck on and the 3Amp fuse on power supply board is blowing...anybody got a pdf of the schematic? I'm going to loosen the top L & R screws of the driver board nex time I start working on it to see it that helps. Tx

It's not going to be a board issue taking out the IC. Something on the playfield is shorting. Since the "Right Flipper Lane Change" switch is part of the column, that's where my guess would be for the short. The fiber separator between low voltage switch and high voltage EOS has likely been compromised.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

I have a similar problem on my Firepower, and although I think the solution might be different I'd like to spin on from some of the suggesions in this thread.

I have a new PinballPCB driver board (http://www.pinballpcb.com/System3-7DriverBoard.html) that keeps blowing the same IC as yours - IC17 which is a 7406. This occurs - usually after a game or two - when the top left pop bumper is activated. The game tilts and the switch matrix is all messed up until I replace the luckily cheap 7406.

I battled with the problem for some time until I thought I had found the solution. By isolating the lamp wires going into the pop bumper the game started working and did so for a year. Now the problem is back. I have taken the pop bumper apart and further isolated the lamp wire so there is really no way that I think that the switch can short to it now, but the IC keeps on blowing. Which leads me to believe that I just got lucky when I thought I had found the problem.

The PinballPCB board is not a perfect fit for all fours screws in the backbox. I have the two top screws mounted, and the board really just hangs there. The IC which keeps blowing is the topmost to the right here: http://www.pinballpcb.com/images/DriverBoard/DriverBoard.jpg
My bracket is different from the one in the picture though, running horisontally rather than vertically. So my question is, does this board need to be grounded through the screws, or can I just elevate it from the bracket by some pcb feet or similar?

If it is not a problem with the board shorting - can it be the switch itself? The pop bumper switch looks ok to me, but don't really know what I am looking at. Can the resistors on the switch blow? Can the switch short to the coil? Any ideas are much appreciated.

Cheers!