I have a Gottlieb Duotron EM Pinball machine from 1974. I've owned it since 1980. I bought it at a local auction here in Minneapolis, MN. The game works properly, I have the manual, schematic and the supplement coin chute circuit diagram which shows different coin chute uses for different parts of the world. I've cleaned and lubricated it as needed over the years I've owned it.
My game came set up as 25 cents for two games. The game has 2 coin chutes and they are set up to mirror each other. I had 2 25 cent coin mechs in the game. I've been using it this way since I got it, but now I'd like to be able to set it up so that coin chute one (left coin chute) is one game for 10 cents and the other coin chute is 3 games for 25 cents. There appears to be options for this as I've set the first coin chute to one coin so any coin that goes into the first chute starts a game. I've set the second coin chute to 3 plays and that works properly. I installed the proper plastic coin slots so a dime and only a dime will fit into the first coin slot and installed a 10 cent coin mech for the left coin slot.
When a quarter is inserted into the right coin slot, the game gives 3 credits. If you press the start game switch the game resets, shoots out a ball and is ready to play. All is good.
When a dime is inserted in the left coin slot it starts a game as if the start game switch was pressed, which is fine, but if you insert another dime it does not give a credit. The main motor cycles and the play field lights go off and then back on but no credit is issued. Is there a way that the first coin slot can give one credit for each coin, or even better, start a game when the first coin is inserted but then when a second coin and subsequent coin is inserted, add one credit for each coin?
This machine is in my basement with 5 other games and a Seeburg V200 jukebox. All my coin operated games take coins and I have a drawer of coins for this purpose.
I can solder as I've changed the capacitors on the Jukebox and other vintage toys. I've also replaced transistors on my solid state games I have a VOM and can check voltage, I'm not great at reading schematics though I have them all for this game. I've attached pictures showing the game, how the coin slots look now and the inside of the game where the settings for the coin switches are.
Thanks in advance for your help.