I have had this game for a couple of years now and has been nearly trouble free. I went through all the contacts when I purchased it "non working" at that time.

While playing a game I noticed I had four bulbs out, one on the left #5 roll over and another on the #3 stand up target, the third just beneath the right Silver spinner, "1000 When Lite" lamp, This was a poor electrical connection in the socket. Last lamp on the check list was the Same Player Shoots again lamp. This too was a poor electrical connection in the socket.

After completing the lighting issues I powered it up. By default the first player is Lite, the Game over is lite and the Match result is Lite. I pressed the credit button, the score motor activates, it uncharacteristically changed from 1 Player to 2 even though only one credit is applied.

The coin door solenoid is energized.
Game Over Solenoid is not energized, however its latch is.
Also the Lock Solenoid is energized.

You can add additional players by adding credits to 4 players. The Coin Counter does not reset at anytime. This is all it does. No flippers, nothing on the playfield is active, just the lights are all on. Fuses have been checked. The DC circuit is not active under these conditions.

I have the Schematic and Instruction Manual though it does not have a sequence of operation. Here is a link to a full PDF Schematic https://www.ipdb.org/files/1871/Sonic_1977_Prospector_Schematic_Diagram_paginated.pdf

I appreciate any ideas you might have in helping me track this down. - Tom

I manually held the Reset contactor in for a few reset cycles. This cleared Game Over Solenoid Latch. The Game Over Solenoid Latch no longer comes on when I turn the power on. I noticed the Coin S.U. does not reset while the reset contactor was held in manually. Just an observation at this point. I did re gap one pair of contacts in the Reset contactor that didn't seem to be contacting very well. All appear solid now.

If I manually hold the Game Over contactor in, I can operate the flippers. This also tells me Reset and Tilt are closed.

If the Game Over relay doesn't latch,
Inspect and diagnose this circuit with Alligator clip jumper wires

Sorry for the confusion, it doesn't even try to energize the Game Over relay, - Tom

HowardR , I should have explained better, the "Game Over Trip" does not energize as it should so the latch hasn't entered the picture as of yet. I have included the drawing of the Game Over Trip circuit. Interesting, I see the Lock Relay can energize the Game Over Trip directly but the Lock Relay automatically energizes when power is applied to the game. I'm not sure when that part of the circuit would be used.

Otherwise it seems the Player Unit, Ball Count Unit open at zero switches thru the Coin Relay. I'll have a look around this circuit then. - Tom

game over trip (resized).jpg