I'm new to the pinball world and still trying to learn what I can from a couple machines that I have. I got a Pinbot (GREAT machine, love this game) a month or so ago now and it was playing but had 4 minor (or what I thought was minor) issues.
1) The top Jet bumper wasn't working and had the coil sleeve melted inside of it. The bumper assembly was taken apart but the game still played ok with just the two bumpers
2) Energy flashers don't work
3)The visor sometimes has to open twice to stay open
4)When the ball is put into the shooter lane it gives an energy value and gives 29,000 points
So I decided to tackle the first problem and bought a new coil and rebuilt the lower part of the bumper. Turned the machine on and tested and nothing. The coil wouldn't fire. I then looked at the CPU board and noticed that Q79 and Q78 looked to be a bit burnt. I decided to replace them both. Put the CPU back in and turned the game on. Within about 5 seconds, Q79 started to spark and smoke. I turned the machine off immediately. Thought maybe I had a bad transistor so I replaced Q79 again. Turn the machine on and again it started sparking and smoking. At this point, I'm way beyond my noob knowledge.
I included the before shots of the transistors below. Would love to at least get this thing back up and playable so my main concern is obviously the smoking CPU any help would be great! Please let me know what pictures to post and I will post them ASAP to help.