I'd have to see the schematic. Do you have one?

I have seen the same problem in my Sonic (built of Williams parts) as well as other Williams machines. The problem is usually in the coin stepper unit. Use a multi-meter to check continuity at each step. Just because it looks right doesn't mean it is. If the machine doesn't have continuity on 1, 2 or 3 players it will always play four. Don't know why. I didn't design it! I chased this problem for three days before I figured it out. Trust the meter over your eyeballs. And if the continuity at the stepper is good, look further up the line. Dirty jones plugs, etc. Good luck!

Shawn

Ideally a single clear, in-focus, edge to edge picture of the schematic, posted to IPDB. The manual would be a nice-to-have.

Hi Willillist, HowardR
about this area --- especially the "encircled orange area". I hope for luck --- in my JPG there are wires "Blue-Red, Red-Yellow, Red-Green, Red-White" --- AND here in ipdb.org the Student Prince manual http://mirror2.ipdb.org/files/2408/Williams_1968_Student_Prince_Manual.pdf shows SAME colored wires on page-19 (ori-17) and page-20 (ori-18) on the interesting Stepper-Units. Locate in Your pin these wires and check --- wires soldered-on ?

IF (if, if) the Student Prince schematics is identical in this interesting area: Write - and we use this Jolly-Roger snippet. Greetings Rolf

0Jolly-Roger-Work-01 (resized).jpg