It could be a bad/shorted diode or a loose wire on one of those switches that are in the same row.
Put the game in switch test and start testing the switches to see if they register properly.Those drop targets are optos so look into the other switches first.

Well worth the money. I was having issues with my JD and that fixed one of them. Just got it "credit dot free) Knock on wood(real hard) Hope ya get the fix for the tilt

Checking the manual the slam tilt is not in the same row as the drop targets.

Check the Slam tilt it's location is on the coin door,Make sure the contacts are not to close.If they are just bend it back a bit.Also,Check the Plumb bob tilt and make sure it's in the center.There is a diode and you can test it with your meter.Power off the game
1.Set meter to diode setting
2.Place black probe on banded side of diode
3.Place red probe on nonbanded side of diode
4.A reading of .4 or .6 should be seen on your meter

5.Reverse the probes,Black probe on nonbanded side and Red probe on banded side of diode.A Zero reading should be seen.If you see a reading it's indicating a bad/shorted diode.

Dawson,Switch 57 is the "G" on the JUDGE drop targets,Those drop targets J-U-D-G-E are all optos and if one is not registering it's due to a bad/faulty/dirty opto on that drop target board they are "U" shaped.There is a coil that pops those drop targets back up..Check the wires on that coil and there is a switch #37 "Subway enter 1" it's were the ball falls in behind those drop targets when they are knocked down.Check the wires on Switch #37 and can be accessed from under the playfield.

Btw,Optos do not have diodes

Nope,Leave them unplugged there's no use for them.

Check the for any loose wires on those targets and test the diodes on each one.

Sounds like The U20 IC on the CPU board has gone bad,Check and see if that IC is socketed on your CPU.

Do the standard switch matrix test to see if it is playfield or CPU board related.
Pull connectors J209 and J207 from the board and Put the game into switch edge test.
Using a short jumper wire, touch each pin on the board of J209 to each pin of J207.
Follow the switch matrix chart in the manual that will show you what each intersection of J209 and J207 should be.See if all switches report correctly.

J207 and J206(Both are the same) runs the column switches.
J209 and J208(Both are the same) runs the row switches.

The U20 chip is located right under the batteries on the CPU,On some boards this chip is socketed but some are not.If it is socketed it can be removed very easily with a small screwdriver,If it is not socketed there's some soldering work that's gonna have to be done to remove it.

Here's the U20 part and sockets should be bought also so that way it will be socketed and not soldered directly on the CPU board.

http://www.pinballlife.com/index.php?p=product&id=569&parent=0

No problem TJ and your very welcome,Here's a link telling you everything you need to know on IC's and circuit boards.Yes the U20 chip removal/replacement should be handled with extra care.
This info is from Clay(He's the best of the best) and has the best info on the net.

http://www.pinrepair.com/begin/index.htm

you can get the chips and sockets at marcospecialties also

For sure there is a reversed diode somewhere in the column/row. The diode band should be facing in the direction of ground. This is common.

Also, check the diodes on the start button, launch buttons, etc.

Are you sure you don't have 1 reversed diode?
I still say you have a reversed diode on the switch that triggers the tilt. Testing a diode, Black wire on banded side.

Sorry maybe I should explain better. To test a diode with a DMM you set the DMM to buzz out resistance (the OHM symbol or diode pic). Touch the black probe to the banded side of diode, red to the other side.

Don't reverse all the diodes. That's a waste of time. For every switch you have a solid wire supplying current, and a 2 colour wire that sends the current to ground when you close the switch. The diode band should be going toward the return (2 colour wire). Do a visual inspection and you are bound to find one reversed. If you've already replaced all the ones in the row/column then none are defective. A switch might just be miswired, in a way that when it closes the circuit is completed without going through the diode.

Don't have much to add, but I have a TFTC that tilted every time I hit the ramp. What was the problem? Nothing but a reversed diode on a switch.

I will get you photo of mine. I have to pack it up next week and will try to take a pic of it before I do. If not it will be the first of next month. Moving

Dawson, got busy and had to pack it quickly. I will try to get it when I set it back up. It is do a good shoppin so I should be able to do it then.

Pictures of the two fire buttons, no diodes, and the 3 target bank (I'd thought that's what you'd needed when you'd posted in my thread). The 3 target bank's not as good a picture as I'd like, but I think you'll get it, if not, I'll try and take some clearer ones.

http://imgur.com/a/eDi0k#0
http://imgur.com/JaidT

Probably on the coin door interface board.

LTG

I wouldn't go replacing stuff unless you know it's bad.

And don't over think this, you have a basic switch matrix problem.

Switch wired wrong, diode reversed, or a short to switch wiring or switch lugs. And it can be anywhere in the game.

Give things a quick look see. Williams used a simple wire code for their switch matrix. Comparing switches helps you understand it. Just white wires and green wires. Different color stripes too but for basic checking just worry about the base color.

On a micro mini switch you have three lugs, two close together on one farther away. The two close together - the outside one gets the white wire and black end of diode, the middle one gets the green wire, and the far one gets the silver banded end of the diode.

Start digging, both sides of playfield and be sure nothing on top of coin door is hitting the front underside of playfield. Go over ramps too for pinched wires and stuff punded into switch lugs.

LTG

Did you unplug that extra plug from the board that you asked about earlier? If you plug that in, you will get all sorts of weird issues.

Just had the same problem with my Embryon. It took pretty much a shotgun approach till I actually found out what the source of the issue is...

- First I replaced all diodes and caps on PF, figured it would be that or one is reversed, nope.
- I had already rebuilt the power supply so i had a solid 5 volts.
- replaced all the 490uf and ~370uf caps at J2/J3, still random tilt/slam reset
- I repinned the connectors for the switches thinking it was a bad connection, nope.
- I then removed the wires from the slam switch, tilt plum bobs and leaf tilt switch, flipper activity would STILL cause it to reset/tilt/slam.
- Changed the PIA's at U10 and U11, nope.

FINALLY, I got around to really going through the MPU -35 board with a fine tooth comb. I also removed all the chips, cleaned the pins, and changed any sockets that looked marginal. Painfully with a DMM i made sure all the resistors were in spec. There were a few resistors that were part of the switch matrix that were more than 5% out of spec, and I decided to replace all the various capacitors on the board.

***There are eleven .01uf 50V caps that are part of the switch matrix and PIA's....I changed all of those with new ones, and guess what? It hasn't reset or tilted since I replaced them (knock on wood) I think you might find this is where you are having trouble.

You have to remove at least one leg of the diode to get an accurate reading.

Diode has a silver band on one end, the other long black end goes to white wire.

LTG