I was just testing my friends Fish Tales main board in my Twilight Zone.
When I put my TZ main board back in I accidentally plugged j-107 into j-106 which is a non used plug for flash/coil power.
Putting the plug back in the correct place did not fix my problem. Afraid I blew something now.
The game powers up but I get a message on the screen that says "ground short, column one"
And my VUK on my gumball machine just pops over and over.
what have I done?
Any ideas on what to check first are appreciated.

After looking in my manual, I only see 3 lm339 chips. U6, U15, and U16.

I also read online the a usual culprit is the ULN2803 chip at U19
Is there an easy way to test these IC's and find which one it may be or could I have messed something up with the opto itself and the chips are fine?

This is what I found online below:
Ground Short - Error Message

It is not unusual to come across an error message GROUND SHORT ROW #. It is very likely caused by a damaged output of the switch matrix column driver ULN2803. Replacing this IC will in most cases fix the problem. What is sometimes more difficult and time consuming is to find the reason why the IC got damaged in the first place. The consequence of not making this effort can lead to repeated problems and more serious damage to the CPU board going way beyond the ULN chip.

The damage usually happens due to a short circuit between the switch matrix and one of the other voltages used in the playfield. It can be the +50VDC for the solenoids, or +20VDC for the flashers, or short between the switch matrix and lamp matrix which works of 18VDC or general illumination which uses 6.3VAC.