Something continuously causes the transistors on the driver board to short and lock the flippers on. I have replaced the transistors with irl540n. The coils show around 4ohm resistance so I am assuming they are good. The game was playing fine and then went crazy. Any ideas where to look next.

That’s what I thought.

I replaced the transistors and then fired the game up. The flippers locked again. I then replaced the transistors again this time I checked the continuity at each point to make sure there were no shorts and that connections were good. The end result was the same. Two shorted out IRL540n.

In the morning I’m going to pull the driver out of my nascar and see if I can narrow it down to the board or the playfield wiring.

Ok so the problem is in the board. My nascar board works perfectly in the hrc. Any ideas. Could the u2 chip cause this? If the bridge was bad wouldn’t it blow fuses and not transistors? Could it be the bridge

Where’s the fun in that

I actually enjoy the feeling of getting one working more than playing. Maybe I am weird lol. I have other games to play. I know the board would be a simple fix and Chris or any number of other excellent, way smarter than me, techs could have it up and running in minutes but I love that feeling of fixing it.

I haven’t given up or forgot about this lol. I have been going crazy trying to fix a bad cats this last week. I am going to get back to work on the high roller casino this week. Possibly even tonight. I’m going to diode test that u2 ic and I’ll report back what I find.

Thank you so much for the help btw

I diode tested u2 and the reading compared to that of u1 and u3. I do not have a logic probe. I guess it’s possible that the chip is malfunctioning under a load. I removed the old chip and put a socket in. I have a new chip on order that should be here by the end of the week. I am going to replace the transistors again and hopefully this will do the trick

I replaced the u2 chip And the transistors. I reinstalled it in the game. The right flipper locked after the first time I pushed the button. The transistor is shorted. I turned it off but I’m sure it would have shorted the left one too.

I moved the board into a fully working nascar to eliminate it being the game itself. The high roller casino is fully working with the nascar driver board in it also.

I’m not really sure what would be causing the issue. It has to be located specifically on the power driver board since it has the same issue in two different games.