Here is my coin door.
There is a piece missing, I found from searching videos that the earlier Sterns had a solenoid that would activate "on" during gameplay to allow coins to be fed, and would sit without power, causing a metal bar to stay in place that would feed the coins back to the coin return if the machine were not powered on.
That same video showed the test sequence, and I definitely do not have the ability to touch a switch and see the corresponding number appear on the score displays, I was watching an older Stern video, Memory Lane, but I'm assuming the diagnostic sequences work similar. As mentioned, I just get that switch test, a number 01 appears on all score displays and the "number of balls" window - but nothing changes that display, not touching a switch or anything else......
I have what I suppose are the two wires that have been soldered to a solenoid plastic "plate" with a diode that replaces the solenoid that was mounted to the side of the coin door.
I can probably find a coin door photo and see what's going on.
Once I get back to my machine, I will also look for the start and slam switches making any contact with the metal coin door.
This could be the cause of my 3 target problem?? The switches on that bank are definitely making contact. The closest 3 is still not registering at all.
Thank you again everyone, getting closer......