Your problem is probably a loose connection if it is intermediate problem. I had points scoring on my Mata Hari from a loose diode wire solder into a hole of a target switch. Solder was solid looking would not pull out or come off but the diode wire had separated from inside the solder. Finally found this problem when I had left the machine on most of the day then went to play it so you can consider the machine was pretty warm. The ghost scoring started when the pop target switch was closed and every time flipper was used scoring started. Pulled glass back and hit playfield and scoring would start. I hit the pop target housing and scoring would start this went on and could repeat it on demand for about a minute or two then it stopped. I started pushing on diodes when target switches were closed and it started scoring. Just a loose diode connection. This loose connection was so slight moving you would of needed a flashlight to see it move. I resolder the diode and problem stopped.

Scoring comes from a closed circuit which is sent to the mpu. I studied your schematics. Try this pull glass off and start a game with some points. Then lift up your right flipper with your hand and hold all the way up and then hit right flipper button and tell me if it scores points. I am going to try my best to help you. Be easier if I had hands on your machine but not possible.

Then try it this with your left flipper.

Now we’re getting somewhere And let’s stay focus on around the left side of under playfield. Before I like direct pics so when your holding up the left flipper up with hand pressing the flipper button does the flipper fall when you let go or does the the flipper twitch because coil is holding it up and scoring starts? Does it score any certain amount of Points or is it random number and keeps going when flipper is up?

Here is what your going to have to do is put a piece of thin cardboard or business card in between all your high score target switches on your playfield. Keeping the circuit open and not allowing any voltage pass through the switch contacts. Do you know if the switch contacts are close enough without touching current can pass. If doing this stops the ghost scoring then one at a time using the left flipper button to activate remove the blocked switch contact one at a time till you remove the one that is giving you the problem. I studied your schematics well and the flippers get there power directly from power supply. They do not emit any source of current to activate scoring.

So you know what switches are scoring too many points?

Did by any chance you test the switch diode or diodes when you had the leafs apart? The diode acts as a switch allows current to flow one way. Guess what happens on a score switch when diode goes bad? It either shorts completely out or can allow voltage pulses to flow both ways. Diodes can either protect say a coil flipper solenoid or allow voltage to flow only one way on like a score switch. If a score switch sends pulses quicker than a blink of a eye. Which you end up with pulses floating in that circuit. Scoring a lot of points! Also you need to replace that transistor you said was bad it almost works like a diode but with higher current. When it goes it blows! Not 100% sure this is your problem but worth betting on. Oh yeah diodes do go bad!

I will look even further later. Out of town this weekend. Some of this don’t make sense to me because of lack of years of experience of searching this problem out but I usually find it it just takes a while. But it makes sense that it does this in a string of target switches. Just multiples the area to find the problem. Sometimes it will act up you just have to eliminate problems.if you have original boards makes problem solving a little longer. See transistors and other semiconductors have electrolyte in them and after many years they dry up. If it is a old machine it is not unusual to replace rectifier, mpu and solenoid board. This cuts down on down time and problem fixing. I am sure you know this.

Hey, found the problem yet? Did you say the transistor by the left flipper button got fried?

Ok your CPU board has a 9 post switch matrix for each row of switches on schematics. Yes the switches on your field has a switch matrix to activate on the cpu board and this can cause scoring if one of the 9 are bad. Also the ground to your flippers are connected to CPU for ground where the power comes from the power board strange but cannot read a path for the purpose for the ground to be on CPU. So if you think it could be the board then yes there could be a short in the switch matrix.

Hey back to my earlier post. I have look at schematics but could not find one for the playfield for the switches and wires for switch matrix. But found a photo online of bottom of your playfield and the 1j10 connector wires go to flippers. Seems there are switches inline with your lower flippers that are connected to a row of switches including EOS which go to cpu switch matrix which connects to a inline resistor strip. Now if any resistor shorts out and touches another switch it can cause ghost scoring. I attached photo it is right above the connector. Why they put flipper switches through a line which passes through scoring switches I don’t know. You could use jumper wires and a meter to check all playfield wires but with a old board capacitors and resistors are going to go bad because of age. That’s a expensive cpu board so fixing it would be cheaper but a new one would eliminate a lot of problems down the road.

83614E53-6CCF-42FD-AB4B-93805C42A8DB (resized).jpeg

D1E28F67-917E-48AA-B648-2857B4D696FE (resized).jpeg