So it blows as soon as you plug J4 into the PPB board? Sounds like a classic failed bridge rectifier. I just replaced one in my Spring Break this morning that failed last night when people where over.

Find the bridge rectifier for this power supply. (probably next to the fuse)

Set your DMM to diode test

Red lead on the Negative terminal of the bridge. Black lead probe the two AC (wavy line) terminals. Each should read 0.4v to 0.6v or so.

Black lead on the positive terminal of the bridge. Red lead on the two AC legs. Each should read 0.4v to 0.6v or so.

A reading of 0v indicates a shorted diode inside the bridge. That will blow the fuse immediately.

I have the same issue on my WWF Royal Rumble.

measure the resistance of every coil using low ohm setting of dmm. if one reads 0ohm or really low, cut the diode off. If it still reads low ohm or shorted 0ohm the coil is bad.

Replace the coil. Make sure you wire it up right / diode orientation. If it still locks on, the solenoid driver transistor is bad (kinda likely to be after a coil burns).

That resistor looks fine to me, i dont really see any burns. I would visually inspect the main driver transistor for the associated burnt coil looking for a cracked open or burnt case. Sometimes solder balls will squeeze out of the case seams too when it has failed. DMM on diode test will tell you if the associated driver has failed.

I'm battling the same problem with my LW3 as you have right now. R16 has fried a couple times on me, and also Q4. It runs the shooter coil, and I've read that if you replace this transistor and resistor, but don't replace the diode on the coil, the transistor will keep frying. So, I'm going to replace my burnt resistor (again), and my Q4 is still fine this time but I'm replacing the diode on the shooter coil as well. I've replaced the diode on the coil before too, just maybe not the last time I replaced the resistor/transistor, and it's funny but it has worked for a long time till now with no problems. The voltage at my coil is 70v, seems normal, so I'm just hoping that this time it'll stay working, not sure what else could be causing it.

*Edit: I stand corrected, Q4 was blown this time as well. Luckily I have the parts on hand, so replacing all including coil diode, hopefully this repair lasts...

Final Edit: I replaced said parts and fired the shooter a whole bunch of times, then felt the resistor and Q4 to see if they were warming up, and both were nice and cool. Maybe I got it this time? Good luck with yours, I'll be watching to see if you get it fixed.

Wow thanks Pinballocks, inappropriate touching is not allowed! lol. I have to check this out on mine, since it could be exactly what's been causing all my problems with burning resistors and blowing transistors. It makes perfect sense, and on occassion I get the right flipper acting funny, and losing power briefly.

I'll bet I have some shorting happening at the same places you had. Thanks again, going to work on it now.

had similar problems plague me on my lethal, which was my first machine. swapped coiled swapped boards still never fully solved. going to have to bookmark this and revisit the old beast. she left a bad taste in my mouth and i got distracted with other machines so been sitting in the corner for awhile

11 days later after working great, my resistor burnt to a crisp , so I imagine Q4 is shot again too. Going to make a separate post to that effect. I also insulated the flipper button from the shooter coil, and I thought maybe that did the trick, but no. BTW my housing on my shooter cover is plastic, and I assume yours is too so no real need to insulate that part.