Around which board? A board in the laser PSU? Also which of the Phoenix connectors did you reinstall upside down? Was it the 3 pin AC line voltage connector, the 6 pin signal connector, or both of them?
If it were the 3 pin AC line voltage connector you reversed, that could have the potential of being really bad if the polarity of the line voltage was wrong (that is if the hot leg had been on the N pin and the Neutral leg had been on the L pin). If in the chance that was the scenario, then installing this Phoenix connector backward would result in sending line voltage into the laser PSU’s ground path.
If you plugged the 6 pin connector in backward, all I really see the potential for there is swapping the low signal (on / off signal) with the PWM pulse (power level signal – think volume control) as well as grounding the WP signal (which is actually done intentionally to bypass that control). So nothing to spark about there.
That is unless scenario 1 is the case (where the 3 pin polarity was wrong), and you installed both upside down, you did the 6 pin first, then the 3 pin. That would be sending line voltage in to the WP signal.