Okay, I did it once, but I cannot get into the Test for Lamps, Solenoids etc using the advance/manual and coin door test button. If have it on manual (Toggled down) it will go into the Audits - if it toggle it up to advance and hit the button it will just freeze the high score to date and the player 1-UP light until I release the test button. I feel like I had a flash that acted this way as well but I could never figure it out. Strangely, I did get this thing to go into Tests once, and I have no idea how I got there! The buttons work fine as I can do in the audits etc without issue and go back and forth.
PS - I know how much everyone loves this game