This JP is the machine that got me into pinball. Bought it as my first machine ~two years ago, got it real cheap, but at the time I didnt feel comfortable taking this project on, as the ower said it had "multible issues". This game went into storage and I bought a game in 100% working condition (WCS) and planed on learning as I go, which felt like a better option since I really didnt know anything about pinball or electronics in general.

Aaaaaaanyway, decided to set the game up a few days ago and take a look, not that I know that much more now than I did then
Checked all coils and fuses.
Visual inspection of the boards and the connectors.
Removed the batteries (still had the original ones, but no leakage fortunately) and added memory chip.
Everything looked okey.

Fired it up and after playing and testing as much stuff as I could the only really thing that wasnt working was the gun trigger.
Checked/reseated the connector, removed the gun and took a look at the switch. Seemed okey. When I tried it again it still wouldnt work. Smart missle was working, but not the trigger.
Decided to leave it for now.

But when I was poking around the very back of the cabinet I stumbled upon a white/brow cable that had split in two. I soldered it together again, and when I tested the trigger of the gun after that - it worked! Not really sure how that fixed it, but I was just happy it worked and I mounted the gun back to the cab.

Now the craziness begins.

I got no flashers that work.
When I push the trigger the shooter lane coil goes banans and fires a few times, along with a few other solenoids. Its really hard to keep track as it all goes so fast, but one of them is the t-rex kickout atleast. Its like the coils trigger instead of the flashers.
Both slingshots trigger the shooter lane coil.
When I cycle through flashers in test mode all I get is the solenoids kicking. Kinda like a ball search.
Flippers are normal.

Whats going on here?
After some googling it seems like bad relays can cause this. Or could it be a matrix issue?

Any insight on what I should do now is highly appreciated.

Found a section from pinrepair.com that explains how to test L/R-relay:

"The first thing to do is to test the solenoid L/R select relay. Turn the game on, and enter diagnostics (entering diagnostics should de-energize the L/R relay; on some games the L/R relay will stay energized after finishing a game because of an after-game flasher light show). Take an alligator test wire and connect it to the metal tab on transistor Q29. Then with the game on and in attract or diagnostic mode, touch the other end of the alligator clip to the ground strap in the backbox (WWF Royal Rumble and later, make sure the coin door is closed). The L/R select relay on the PPB board should click "on and off"; it will click on when the transistor is grounded, and off when not."

I did this and I got a click when I grounded and one when I removed the alligator clip. Tried a few more times, like 5-6 all worked, and after that it stopped clicking. Reseated the clip but no change. Restarted the game. No diffrence.

"Another way to test the L/R relay is find the 1N4004 diode next to the L/R relay. This is the blocking diode for the relay. If the Non-Banded side of this diode is grounded using an alligator test lead, this will also energize the relay. On games with PPB boards, remember the L/R relay is mounted on this board (and its diode is right next to the relay). On the first two DE games that don't have a PPB board (Laser Wars and Secret Service), the L/R relay (if the games have one, I'm not sure!) would be mounted under the playfield."

Tried this aswell. Same thing, worked 5-6 times then it stopped working. Here I could reset the alligator lead and the clicks came back and yet again stopped after a few clicks.
When I direcly after this tested Q29 it started to click on/off again, but only a few times and then once again it was dead.

Tested Q29 with a mm and it gave a reading of 2,2-2,5. Not sure if thats normal, but I guess so since most of the other transistors I tested gave the same result.

Thoughts?

Anyone? Not sure where to go from here.
Might the relay be going bad and needs to be replaced?

I have reflowed all solder joints on the relay and also some other solder joints that didnt look as they should.

I havent put the board back in just yet, cause I saw this:

aviary-image-1532115798519 (resized).jpeg
aviary-image-1532115681657 (resized).jpeg

Pin 14 on J1 has come loose. I guess I need to replace the headers? There is no wire on the connector that goes to pin 14 but it has a trace on the underside and watching the schematics it goes to a transistor.

aviary-image-1532117591419 (resized).jpeg

Actually, you are right. So I did just that.
Not sure if its was the reflow or the fix of the broken header, but now the flashers and coils works as they should.

My first ever board repair, check

Thanks everyone who replied!