Sounds like a potential issue with a component in the machine , but just guessing

I had a shadow for 15 years and had this problem twice, I think this will be your problem-

The sanctum has a timing element which is important for it to work. This is what happens when you hit the sanctum:-

1/ The ball crosses the opto which triggers the magnet.
2/ The ball gets grabbed by the magnet.
3/ The magnet drops the ball momentarily and the sanctum wall target drops. (timing important here).
4/ The ball crosses the opto path again as it rolls back down briefly, this triggers a second short momentary fire of the magnet to pull the ball up through the magnets field and up into the sanctum.
5/ The wall target closes.

I think you will find the problem is that the ball is not rolling back through the opto in time in stage 3 above. This is important if the timing isn't perfect the machine will assume a mechanical fault with the mechanism and drop the target for the rest of the time until the machine is reset. This gives the machine the ability to play a game if this complex system goes faulty.

The fix: This is invariable caused due to a small divot in the playfield where the ball is grabbed and dragged across to the sanctum time and again. The ball is not rolling back across the opto in time so the machine shuts the feature off. The divot is keeping the ball still for too long. The fix I did was to dig out the playfield damage, fill with car filler and then paint grey to match the playfield. The ' To The Sanctum' decal may have to be replaced or mask it off. I then put a small piece of mylar over the area to help keep it from re occurring. There only has to be a tiny divot to totally wreck the timing issue( like paint missing on the playfield). This is also why it works sometimes, it will get worse and worse until the playfield is made perfectly flat again.

The magnet area does get hot after a good few games, I think this helps the area get scraped/dented. The target switch does have to work reliably but if it works in test mode then that can be ruled out.
Good luck I hope this is helpful! Let us know how it goes!

I had the exact same problem with my TS. I had moved the game, and since the floor was uneven, it wouldn't work. Adjusted the pitch of the game, no more problems.

As Paddy says, it is very sensitive.

@Paddypaws thanks for the great explanation of how the ball lock works.

Axl

I just got a Shadow and I can't get the target to drop once the magnet has the ball. Target drops as it's supposed to in test, but not during game.

Maybe the fix for yours will give me some insight on my issues...

Levi here is a video of the action. I took this after a restore for a client. Maybe it can help. Watch the ball break the optos.

Also make sure your optos are working, Cleaned and aligned. This is the same for the drop target switch which gets battered and misaligned often.

The switch actuator also gets bent a lot causing issues.

I've seen this before on my own Shadow. If I remember correctly, it's because the ball is going into the lock area and rolling (bouncing) back off the lock switches. If it bounces back too far and the switch is open too long, the game won't try to lock any more balls. I don't know if this is by design or a bug in the programming. The wall target usually starts doing weird things at this point too.

Rob

Second vote for a divot. Common issue, easy enough to test. Next time it locks help the ball roll back if it work every time with the help then you know it's the dot and everything is working correctly. I'll give you one big advice that no one mentioned in all the sanctum repair threads, after the repair of the divot don't use the clear from Home Depot it's too soft and will get crushed again under the pressure of the magnet buy a can of automotive clear it drys much harder.

Divot. Tape a credit card over the area and problem will be magically solved. A quick fix may just be a couple pieces of Mylar just to add a little thickness over the divot. As the divot warms up after play that area softens and just holds the ball a fraction of a second too long.

Should be an easy short term fix

Go into tests and check the switches in the lock lane. Adjust as needed.

Test the drop target switch too. Be sure the wiring to the switch is configured for normally open. Or take a photo of the drop they switch wiring and post here.

Mine was having this issue with no divot. Every so often it would fail and the drop target would stay down. I ended up removing the drop taget (20 minutes before a party) and rebuilding it and I believe replaced the switch. It has worked fine ever since. I forgot what was wrong but it was something with the switch there. Sorry I cannot be more specific. I cannot get the glass out of my game right now as the game room became the holding area for the rest of the house during renovations.

All sorts of weird issues come from the combination of the magnet/drop/optos. Mine doesn't look like it has a divot at the sanctum, but it does and it effects the ball roll unless the game is set up just right with regards to leveling and inclination. Same with the lock switches and drop switch - very picky and it will drive you nuts trying to find that sweet spot. So, you might be seeing an issue like the drop falling immediately when it's hit and it could be related to any of those things - and the game's programming at that point isn't going to help you out either when it senses errors. Have you tried messing with different combinations of leveling and inclination? Might help to set it up pretty steep or slightly to the left or right and see what happens.

Maybe a physical problem with the small plunger that releases the drop - so that when its physically hit on the second and third lock, it slips and falls even though it shouldn't? Maybe the spring not forcing that plunger hard enough to hold the target up when hit? Is your wall target cracked or bent at the bottom? Just some thoughts. Shadow does some craaaaaazy things sometimes and it can be frustrating for sure...hope you get it solved!

As I said in a previous post, I believe the switch is bad. Can you send me a picture of the unit? Perhaps it will jog my memory so that I can tell you exactly what I did. But I think I just replaced the switch.

As pincredible, mentioned the switches in the lock. Its a good clue if it only happens on locks 2 and 3 then the problem is probably the micro switches in the lock. These have to be adjusted perfectly so they trigger very lightly and don't push against the ball hardly at all, otherwise the ball will not sit directly on the switch but they must trigger reliably. otherwise the machine doesn't know how many balls are in the lock. I ended up replacing those switches because mine were troublesome when I bought the game.

Did you test the wall down target switch # 51 in switch test?

Is its actuator straight and not bent?

Is the micro switch angle on its mounting plate correct?

Is the switch intermittent? Bad internals? Wires etc?

The lock switches must be adjusted sensitive to register without trapping the ball which they do very easily in that tight space.

Once again make sure the actuators aren't deformed and or loose with sloppy side to side play. Did their anchor pins get worn on the switch bodies? etc.

On all of the Shadows that I have repaired and or restored the issue you are having was due to the Wall down Microswitch being at fault for various reasons or the ball lock switches not being adjusted correctly.

Did you read my post and check for that issue? I know for sure that will cause the issues you are seeing.

Rob

It's likely one of the 3 switches in the ball lock.

I think it's really narrowed down that the issue could be one of the many suggestions on this thread

Post padding? Dry humor? Not the sharpest Crayon in the pack?

Check the target down switch. If it doesn't sense the target has dropped, the magnet will hold the ball and then just let it drop.

I was having a magnet noise issue with my Shadow. In researching I came across this. I believe this is your problem and was mentioned in above posts.

The main problem is that for some god-unknown reason the micro-switches (Switch’s #63, 64 & 65), appear to become more resistant to the weight of the pinballs.

This results in the magnet throwing the ball into the lock but unfortunately they are not heavy enough to activate the micro-switches, this causes the balls to stick on the switches. Unfortunately, this causes the machine to think that the wall target assy. has become faulty, therefore marking it as bad and disabling it.

The solution to this problem is to lift the playfield up and rest it against the backbox, then locate the switches under the playfield (with the game turned off). With long-nosed pliers adjust the micro-switch arms, so that only a tiny amount of pressure is require to activate the micro-switch. Then using switch edges test (T.1) place the balls in the lock and test all the switches and ensure that they no-longer present too much resistance to allow the ball to pass.

I was going to say that you might try to drop one ball into the lock area while in switch test mode. With one ball in the lock you might toss a few against the wall and see if any of the switches in the lock area are flaky etc. you might also try this with two balls in the lock as well. Sounds like a flaky lock switch to me which causes the game to think the ball that was locked isn't there any more so it drops the wall waiting for that locked ball to be returned....

Whenever I have had problems with a ball locking this is generally what happens. I get the lock lit.... lock the ball and it doesn't make it into the lock... so the game leaves the wall down and the next shot into the sanctum instantly goes into the lock. At that point the wall goes back up and the game acts like it will work normally again.... much of what you have described sounds like the game is losing track of the locked balls and trying to compensate for it.

No, he is full of pearls of wisdom (see bad schtick) in his own jjp tech help thread.

Mine worked fine in test too. Damn I wish I could remember the exact issue...

Have you tried playing with a credit card taped over the sanctum?

Yea Mylar probably isn't enough to rule out the divot

I think that the post rubber is probably fine, and yes , game should NEVER have liquid spilled on it , must be kept dry as you mentioned, but I don't find the humor on that.

Also , back in the EM days some would use crayons for touch up , on newer machines it would not look nice

No I just try to help where needed , I don't recall though , but does shadow have a bell in there instead of a knocker ? Like space shuttle , love when u ring the bell too

If it's not the divot it's most probably the lock micro switches...the guys in the post above are absolutely correct if the switches are flaky it will result in a couple of weird behaviors. I think you've already narrowed it down to switch 1 in the lock. Don't try and bend the tab that's only a temp fix, put a new switch in.

Once the wall target fails just one time, it will stay that way until you turn the game off band then back on. It was designed to play with the wall down and inoperable to keep the game running and earning money.

I owned one for 2 years and went through this same thing. I had a divot and fixed it and it did no good. My problem was in the 'wall target down' switch. Make sure the target is triggering the switch. If the game thinks the target is still up, it won't throw it into the lock. It doesn't matter if it works in test, you are just telling the wall to drop and raise. If the target does not trigger the switch, adjust it, turn the game off and on again and re-try. It is very frustrating, took me a few days of tinkering, but after I got it right, it never malfunctioned again.

I also took the whole thing apart and cleaned everything just to make sure the wall target was sliding up and down smooth.

Is it possible the balls are a bit magnitized? So they are staying semi stuck to the magnet core under the wood.
I know you said it's not the divot. But I had this problem, and it was caused by a divot in the sanctum area. And the switch arm on the wall drop target being twisted a bit.

Basically as others have said. Repair the divot 100% first. check the switches. Switch arms how much pressure is needed to trigger them etc. Clean the optos with a q-tip and Windex. And not just the sanctum optos. ***All the optos. JD has a similar issue where one intermittent opto makes the others go wonky, and the crane magnet.
Check for magnetized balls.

Because if it works fine in test rolling a ball at it. And in game it fails. It is because of the speed it's travelling when it hits the optos that is making it not work. So clean them good and test with the flippers shooting the ball at the sanctum in game mode.

If that fails.... gasoline and a match.