Quoted from PinJim:Well, three different IRL540 transistors were tried, none worked. The driving SN74HCT374N chip was replaced. The 5V is at 5.1V. I verified all resistor values in the circuit. I probed the SN74HCT374N output and can hear it pulsing when the flipper is activated.
There are some other subtle differences, mostly around capacitance and timing. Not sure if those are a factor for the whitestar flippers, since the outputs are strobed (not held on). Not sure. But agreed, something seems odd.
I’d love to hear from someone else with a rottendog whitestar board that’s had to replace the flipper transistors.
I know this is old but thanks to it I fixed this Rottendog MPU011C. Maybe it was eBay IRL540Ns.... working on a Rottendog MPU011c and one of the Special Solenoid was locked on. Replaced transistor with the IRL540N. Would blow after one or two times firing. After HOURS of chasing down all other options, and 5 new transistors I switched a 13N10l transistor from an unused circuit for this game and boom. Now it works no problem. So maybe just bad chips but I definitely had this issue!
