I was reflowing solder on a SDB on a Future Spa. No solder bridges that I can see but it's possible that when I put the J3 connecter back on 2 of the pins were actually touching. J3 started sparking badly. Turned it off immediately. Double checked the board and put it back in and it's still sparking. Did I maybe fry a bridge on the rectifier board? Any suggestions on what to check? Thank you.

Thanks Quench. Let me know if you need more pictures. To back up a bit, original issue was the ball gate was not working in game mode or during the solenoid check. I had tested the transistor Q17 with a meter and by shorting the metal tab to ground. It tested ok and shorting the tab caused the gate to operate correctly. So I resoldered the header pins. That caused the first sparking incident. After the first sparking incident, Q16 shorted. Replaced both Q17 and Q16. After the 2nd incident, Q16 shorted again. Rectifier board is a mess with old burnt header pins and corroded fuse holders. I don't have the game with me so no pictures, but it was way overfused. 1 fuse was a 20 amp where it was calling for a 3 amp. Ridiculous. Corrected that but that didn't stop it from sparking the 2nd time. New XPin solderless rectifier board has been ordered as has a new SBD but I would still like to know what happened here.

I know the flux needs to be cleaned up. I did not resolder J3 (only added flux but didn't resolder it) because there are a lot of solder bridges there that look intentional so I didn't want to mess with it. As it turns out that's the one that sparks.

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Solder in the yellow boxes is good, no shorts there. However, that red box is probably it. The green coating is definitely scratched off there. I get the meter to buzz if I touch from the red box to staple jumper pin at the top right. The plastics spacers were all in bad shape. Brittle and broken. I’d be willing to bet that outer trace is shorting to the sheet metal in the backbox. I won’t be able to see the game until next weekend but I’ll report back.

Any ideas about the original issue which is the gate not opening? Thanks guys.

Thanks Quench for the info. I’ll report back next week.

Well I found it. I must have touched up a few pins on J3 and shorted pins 5 and 6. Sorry for the blurry picture. It also took out one of the bridge rectifiers and burned up the 20 pin connector on the rectifier board. Nice going. Geez! Still waiting on a new rectifier board.

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Thanks. So that would be F4 which should be a 5 amp. This Xpin board that I ordered shows that F1, F4 and F6 may need to be changed according to the particular game. I believe F1 will need to be changed to a 20 amp. It looks like the board ships with a 10 amp. Can anyone confirm that? The schematic is pretty faded. I plan to hook up one board at a time and verify the voltages before moving forward. That's how I discovered a bridge was blown on the old one. I only had around 70 volts on test point #2.

https://xpinpinball.com/product/xp-bly2518-ebr/

Finally resolved the original issue of the gate not working. Even with a new SDB it still wasn’t working. Bad pin at J4 pin 11 of the SDB. Repinned it. I only wrecked two boards and it was a bad connection all along. Quite a learning experience. Thanks guys. Incidentally if anyone is interested the new solderless rectifier boards from Xpin are excellent. The connectors hold the wires really tight. Thanks guys.