Hello! Ive been restoring an EBD. New hardtop playfield...LED kit....i serviced it all and it works beautifully except for 1 issue. This has been tearing me apart as I understand why it can happen but I don't understand why it is happening. I am hoping someone here can give me some insight. On to the issue:

The issue is simply this, when the signal for the 4 drop target reset happens, it resets the 4 drop targets as normal but simultaneously fires the 2,10 drop target. In test mode, the 2,10 will fire normally alone and not cause the 4 drop target to fire. Only happens when the 4 drop target solenoid fires does the 2,10 fire erroneously.

Here is what I did:
I know that those 2 solenoids share a connection and the relay will switch between. A bad diode could cause this symptom. So i started probing. checked solenoid expander board. 555 incandescent bulb is working(i did not swap this particular one to LED). All GI is working and relay is switching. I believe the relay was changed at one point(not by me). I cant confirm it was changed but it looks way too new to be original. Reflowed all connections on SEB for good measure and checked diode which was good. I checked the 2 diodes on the 4 drop target reset solenoid and the 2 on the 2,10 drop target. All checked out normal....i replaced them anyways. No change in result. Checked diodes on SDB for the hell of it, all checked fine. Checked the driver transistors even though I didnt think they were the issue....all checked out ok.

I'm confused as to what is wrong. It isnt that complicated of a circuit and it is driving me mad as to why I cannot seem to understand what is happening here. Could someone help me end my madness?

Edit: picture of the schematic. Anotger bit that is confusing me here is the image of the SPDT relay switch. Im reading this as the normally closed position which should be keeping wire 67(i dont have the wire color code handy) active and when energized activates line 81. When I was in the test mode it was reversed as to what the schematic says.
20200818_182709 (resized).jpg

Gotcha. Didnt think of that. Ill do that tomorrow when I am back at my shop. I believe one of the two 7 drop target solenoids was replaced. Thinking it was a 3 lug coil to a 2 lug coil with one diode across...

I had my helper take a video of the 2 coils(im not there today). Apparently both were replaced on the 7 drop target reset. One coil(when coil is facing upward) has 2 red gray on left side, 2 black white wires on right side. One diode across the 2 lugs with cathode towards black white. Other coil has(coil facing upwards) same arrangement of wires and 1 diode across the 2 lugs with cathode facing red gray. Yep....there is my problem....damn. I was so focused on the orange brown that i didnt think to look at the other side as I was assuming the previous repair was done correctly. Well.....nope. I should know better!

Screenshot_20200819-140245 (resized).png

Screenshot_20200819-140421 (resized).png

this is for my understanding. To make sure im understanding properly what happens in this case. Since the diodes are not hooked up properly on the 7 drop target, reverse voltage is allowed to pass through the circuit. There is now a free charge in the gray red wire. Electricity will take the path of least resistance to ground and the 2 10 coil is next in the path thus being the shortest easiest way for it to ground. This is why the 1 9 coil does not fire. The 4 drop target then fires and the relay is back connected on wire 81(orange brown i think)which is shared with the 2 10 coil. Since the charge is not coming from the reverse direction to the 2 10 coil, its own diodes do nothing to stop the coil from firing because it technically is coming from the correct direction in the circuit and the relay has completed the circuit so the 4 drop target fires along with the 2 10 coil.

Would this be a correct explanation of what is happening here? I just want to understand as well as fix.

Gotcha. Much appreciated. Your diagram was very helpful! Ill report back when i fix it tomorrow.

So i rewired it by making a 3rd "lug" on each of the coils by wrapping extra pieces of leads from the diodes. Working nicely!!!! Issue fixed. Thank you again!