The way to read the schematic for the two Target Reset solenoids is:
- the A & B Target Reset solenoid fires when the Score Motor 2B switch closes and either the Target relay switch closes or the Coin relay switch closes.
- the C & D Target Reset solenoid fires when the Score Motor 2A switch closes and either the Target relay switch closes or the Coin relay switch closes.
The Coin relay likely fires (and resets the targets) when you start a new game while the Target relay is used during a game whenever the targets need to reset. If your C & D targets reset successfully during reset and during the game that means that the Target and Coin relay switches are working correctly, together with the Score Motor 2A switch.
So if you cleaned the Score Motor switches and the A & B targets still don't reset reliably there's something else wrong. There are a couple of things you can try.
First if you have an alligator clip test lead, connect the solder lug of the C & D target reset solenoid with the grey-white wire to the solder lug of the A & B target reset solenoid with the blue-red wire. With the test lead in place do whatever you need to do to get the C & D targets to reset. If they reset, and the A & B targets reset too, that proves that the A & B target reset solenoid is ok and that it's not getting the power it needs through its own circuit.
The other thing you can try is to check the circuit that drives the A & B target reset solenoid. If you have a multimeter, unplug the game, set the meter to the lowest resistance setting and clip one test lead to the blue-orange wire connected to both score motor switches and the other test lead to the grey-white wire on the solder tab of the C & D Target Reset solenoid. Slowly turn the score motor cams by hand and when the two score motor switches close you should see your resistance measurement drop to something less than 1 ohm. That's what a good switch (the score motor 2A switch) looks like when it closes. Rotate the score motor cam a couple of times to convince yourself that you can tell the difference between an open switch and a closed switch with the meter. Then move one probe from the C & D Target Reset solenoid to the solder lug on the A & B Target Reset solenoid with the blue-red wire and repeat the test. Now instead of testing the Score Motor 2A switch, you're testing the Score Motor 2B switch. Does it behave and measure the same as the Score Motor 2A switch?