Good afternoon everyone. I'm brand new to the site and brand new to pinball (not playing, but owning and fixing!)
I purchased a Data East Lethal Weapon 3 a few weeks ago, and it has probably been played 3-400 times in the last month. There were a few hiccups stemming from transport (a couple broken solder points and such) but otherwise it was playing great until last night. Last night while playing a game with my daughter, the ball launch coil melted down. (smoke, brown goo, too hot to touch for 15 minutes) it's an 090-5001-OT. I had a spare so I soldered it in and turned the game on briefly before I had to leave work. It came on and nothing got hot, but the ball launch still didn't work, and, perhaps more importantly, neither did the flippers. They barely twitched when they were hit, like something else was stealing all the power.
Ok, so now comes my foolishness of jumping in before I know what I'm doing.
I ohm-tested the melted coil, it was 2Ω. The new coil held steady at 5.5. I pulled the power board and discovered a couple things: R15 (a 220Ω resistor) was burnt black; the 7A fuse at the top of the board was blown, and the Q5 transistor was completely gone. (I found out later that Q5 is the knocker, so doesn't affect gameplay)
So I went and got some new fuses and resistors, soldered them in, reflowed a couple of sketchy joints on the back of the board, and put it back in.
Turned the machine on and the Ball launch coil immediately activated. (which, from my limited understanding means the old coil was stuck on and that's probably why it burned up?)
Turned it off and on a couple of times, same result.
I also noticed the old coil was missing it's diode. Not sure if that has something to do with it.
Then, I thought something really silly, in retrospect. "maybe I just wired the coil backwards?"
So obviously I reversed polarity, turned it on, puff of smoke, and dead.
Fixed the polarity and installed another fuse, turned it on, fuse popped immediately. The new coil now ohms at zero.
So. I'm just now trying to learn how to even read electrical diagrams. This is not my skillset, but I need to learn if I'm going to own pins. So here are my questions:
Did I kill the coil by reverse wiring? Or just the diode?
Where do I go from here? I have a brand new XPin PPB on the way, but don't want to install it and ruin it immediately.
There are no obvious shorts or broken wires, is it possible the coil meltdown burned up the resistor and popped the fuse, then the reversed polarity blew the diode, then the blown diode blew the second fuse? Or is there something else I should check?
Is the new PPB going to fix it, or am I going to waste the money on the board because the "something else" still isn't fixed?
Thanks for reading, and any direction on diagnosing and fixing this would be greatly appreciated. Cheers!
Joseph