Removing the battery in this case will not help.

Based on your pictures, the trace the leads directly down from the last terminal of the battery holder (the negative end) should be connected to pin 12 of U16 and then on to pin 9 of U20. The thin trace from the battery holder to U16 looks really fragile and may have been weakened when the battery holder was replaced. Pressing on the battery holder may have broken that trace. Without that trace, U16 and U20 are not grounded which would cause all sorts of problems.

That trace needs to be repaired.

A short piece of thin, insulated wire on the back of the board works well. Just make sure it it insulated so it doesn't short out to the backbox or other pads on the back of the board. Jump between the battery terminal pad and pad on pin 12 of U16.

That trace should be there. I think the other poster was concerned the trace was grounding out to some of the pins on the other side of the chip.

To test the trace is connected, make sure the game is off. Put your meter on ohms. Put one lead on the battery terminal and the other on pin 12 (each circled in RED in this picture. You should see zero ohms or really close to zero.

Image002 (resized).jpg

I wouldn't try and solder on that board with it in your game. Take lots of pictures of the connections. Removing the board amounts to removing all the connectors and loosening 6 screws, sliding the board up and off the screws through the keyholes.

My guess is that as you pressed on the battery holder to remove and install the batteries, you flexed the circuit board enough to break that fine trace that looks like it was damaged and poorly repaired when someone replaced the battery holder.

You soldered the wire to the wrong chip. It needs to go to pin 12 of the chip above it. Look again at the picture I posted with the red circles.

Unfortunately, grounding pin 16 of the ULN2003 most likely blew that part of the chip, which will cause column 3 of the switch matrix to stop functioning.

The pin on that chip where you soldered the wire is an output. Typically when your tie outputs of this type to ground you blow components. Not a guarantee but probable. If it blew, all the switches in column 3 will no longer register.

You have 2 choices:

1) Replace the connector with a new housing and crimp pins. This is much more expensive as there are tools to purchase.

2) Reinsert the wire in the connector housing using a punch tool and/or replace the IDC connector with a new one.
https://www.marcospecialties.com/pinball-parts/77-IDC-A100
https://www.marcospecialties.com/pinball-parts/5792-12116-09

You can use a small screwdriver to try and press the loose wire into the existing connector but in my experience, you are asking for trouble in the long run. Better to buy the proper tool and a new replacement connector. Carefully cut one wire at a time off the old connector and punch it onto the new connector with the punch tool.

The ultimate better would be option 1 - to buy a housing, crimp pins and crimping tool and use crimp-on connectors but that is even more $$$

Start a game and make sure all the switches on the playfield work. If you damaged that chip, some of the switches will not register.

Congrats on the progress!

The wire that fell out of pin 1 of J206 is not ground. It is column 1 of the switch matrix. Best bet to ensure all the connections are solid on J206 is to replace that connector.

https://pinside.com/pinball/forum/topic/t2-phantom-escape-key-pressed-not-the-switch#post-4879020