You might have shorted 12V to ground when you did the soldering. Were you working on the LED board or the phototransistor board? The LED board is closer to you when you're facing the machine.

J1-12 should have a gray-yellow wire punched down into the IDC in the connector. The next slot J1-11, should have no connection (based on page 3-19). The next slot over should be black wire and the next slot should be the key.

I think the prior poster envisioned a looped wire (e.g., the grey-yellow is punched down in j1-12 and looping over to J1-11). That is what page 3-18 suggests, but I think J1-12 and J1-11 are connected on the PCB, so you only need a connection at J1-12.

My connector also had the grey-yellow wire cut, ends stripped, ends twisted together and pushed in the IDC at J1-12. Sounds like yours is similar, but also soldered to location J1-12. Yours sounds fine. If somes phototransistors are working then the board is getting 12v. Ideally you would want to replace the connector, but I hate repinning connectors

Have you checked that all the LEDS are working? That could make switch 61 think that there is a ball there all the time.

As atomicboy said, looks at the LEDs through a camera (phone works) with the LED board powered. All the LEDs should be emitting light (mine looked sorta purplish through the camera). I had two LEDs out causing all sorts of nonsense

I'm not 100% sure, but I don't believe the photo transistors light up during the camera inspection. The LEDs should emit infrared light. If you have an LED that did not light up, then replace that for sure

The LEDs should be on all the time. It's an infrared LED. The part number in the manual for the LED is 5671-12731-00. If you google that number, you can find the replacement. I bought a generic IR LED at radioshack because I didn't want to wait for shipping.

These LEDS have to be installed in the correct orientation, with the cathode connected to ground.

The packaging for the LED should indicate which is the anode and which is the cathode. A general rule I have seen is that the longer leg is the anode.

I don't have the board in front of me, but the anode (longer leg) gets connected to a resistor and the cathode (shorter leg) gets connected to ground. When you remove the broken LED, figure out which leg was connected directly to a resistor. You should see a trace from one of the holes to a resistor leg. That is the through hole where the anode should go.

Not sure what you mean by emitter and transmitter? I guess the LED board would be called an emitter, because all it does is emit infrared light.

You would use the emitter, but it needs to be infrared.

You can order to the correct part online. I think there are some threads on where to get the correct parts. Someone above mentioned great plains electronics. Or google that part number 5671-12731-00 and you get results.

Also, there is a company that sells the whole LED board http://www.greatlakesmodular.com/. Look at the DCS-TT, it says it works with STTNG

I didn't realize that, good information.

If a known working LED does not work in that location, something on the board is messed up. Make sure that the resistor that is connected to the LED in question has a good contact with board. I had one with a leg that was cracked. I think those resistors are known to move around, possibly breaking leads or cracking solder joints.

I have no idea on the GI in the shields. Never had that problem