Winged Monkey misbehaving? Won’t pick up the ball, or picks up nothing?
Check the operation of your Magnet Sense Switch!
Posted by Daniel Tonks on April 24, 2014 at 6:06 AM
Sorry that I’ve been so remiss in posting here lately – but between life and enjoying the amazing new WOZ software version 3.0 released not too long ago, I haven’t had much time to film videos or write up tutorials. However, I do have something new for you today: I’ve taken a bit of footage filmed earlier this month and created a quick video testing tutorial to address an issue with the Winged Monkey that’s recently cropped up with some JJP Wizard of Oz owners.

You’ll find the video embedded below (be sure to click on 1080p!)... and after the video, a detailed write-up of exactly what’s going on!

Shortly after WOZ version 3.0 software came out, quite a few owners – including myself – noticed strange behavior in the gameplay behavior of their Winged Monkey. One such symptom is that the monkey initially refuses to pick up the ball: the magnet grabs it, the monkey starts moving down, but before it’s halfway there it suddenly reverses and returns home... and the magnet releases the ball.

After three or four tries, it appears to start working normally again... but don’t be fooled, because it’s not!

What’s going on here?
One new feature in version 3.0 software is that the Monkey Magnet Sense Switch is enabled for the very first time.

The... what? You’ll be excused for not having noticed this before, because it looks the furthest thing from a switch and isn’t well documented. It is, in fact, a tiny circuit board mounted near the Monkey Magnet on the rear of the backboard, and its sole purpose is to detect when the Monkey Magnet has successfully grabbed a ball. Quite interestingly, this is both a non-contact and non-optical switch – it works by detecting a magnetic field through both the backboard and metal rails.

What this switch does, is prevent those annoying situations where the magnet fails to grab the ball (usually due to a weak orbit shot that doesn’t come close enough), but the game doesn’t realize that’s happened – resulting in the monkey making the entire journey down to pick up and deliver... well, nothing at all.

Granted, when the Winged Monkey does drop off the sum total of bupkis the game realizes what happened and awards a “virtual lock”– but there is a downside to this behavior. If a ball was already locked in the Witch’s Castle, then the game releases it before the monkey arrives. Which means if the Monkey wasn’t carrying a ball, then that player now has an undeserved 2-ball multiball – a definite no-no in competitive play!

Pinplay Photo #82
So what’s happening now?
The example I gave earlier, where the Winged Monkey fails to pick up the ball several times, is the result of a Magnet Sense Switch that isn’t working whatsoever – meaning it never detects that a ball has arrived, even when it clearly has. Thus the game believes every grab was a failed grab, and the new code cancels the Monkey pickup and turns off the magnet.

After this happens several times in a row, the game “wises up” and decides that the switch must be actually be broken, and marks it bad. It then compensates by assuming that the ball has always been grabbed, resulting in operation identical to software versions prior to 3.0.

Another possible symptom is a game with what seems to be a functional Magnet Sense Switch that randomly experiences issues with the Monkey “delivering nothing”. This would be the result of the sensor being too close to the magnetic field, which would cause it to trigger whenever the electromagnet is activated and not only when the field has been enlarged by the mass of a captured ball. This condition will also result in the game behaving exactly as it did prior to v3.0, since as far as the game knows a ball is always ready for pickup.

Now how do I fix it?
There’s a special Device Test in the service menu to check the correct operation of the Monkey Magnet Sense Switch (see the video for more).

If your Magnet Sense Switch doesn’t seem to be triggering at all, then you should first check to see if it works at all. Find a strong magnet and then remove the switch from the game (you can also try testing while it’s mounted, however this did not work for me). While on the dedicated switch matrix screen, wave the magnet around both sides of the sensor (the small 3-pronged black chip at the end of the switch), and see if you can make it trigger. If it does, then your switch works, but either needs to be flipped 180 degrees (facing the small chip towards the backboard instead of away from it – this is due to a harmless polarity issue), or it must be moved closer to the magnet.

Pinplay Photo #83
However, if your Magnet Sense Switch is triggering all the time, then it needs to be moved further away from the magnet.

I recommend testing new mounting positions using masking tape until you find one that works reliably. Keep the height the same, with either the protruding pins or the connector (depending on orientation) tight against the bottom of the playfield. Also, don’t forget you can mount on the opposite side of the magnet to avoid the troublesome metal bracket in the original location. Do be aware that the margin between “not triggering at all”, “triggering perfectly” and “triggering all the time” is quite small, and note that slight changes in angle can significantly impact your results. Be sure you test with the switch pressed firmly against the backboard to emulate the exact angle it will be at when screwed down, and not loose and sloppy.

I also recommend that once you’ve found a working position, you switch off the game and come back several hours later after it’s cooled down. I’ve found that if the magnet’s hot, a marginal location is more likely to falsely test fully functional – and once the magnet’s cooled down, the switch will begin triggering whenever the electromagnet is active, and not only once a ball is grabbed as needed.

So, check out the video tutorial above... and if you have any questions, feel free to ask!

Recent Related Blog Posts

Numerous in-development improvements on their forthcoming game showcased at IAAPA.
Additional modes, more lighting, lots of bug fixes!
They’re right there, hiding in plain sight...
It’s the extra ball that makes all the difference – and a high score!
Tag Central
Your name:
Your email:
Your email is used for verification only and will not be published or spammed.
5 reader comments
Thank you for this. It saved my bacon. I also had to pull back and angle it.
Thanks again!!!
Thanks guys - this fixed the problem on mine where the upper mangnet released before the Monkey would actually pick the ball all the way up. I had a hard time finding just the right spot where the Monkey Magnet Sense would only trigger when the ball was captured and not just when the magnet was manually triggered but eventually I found that mounting the sensor lower on the backboard and at just the right angle fixes the issue. To be detailed, I made sure that when I hit the Enter button (remember to pull the high power interlock button out of the magnet won't have power) to manually trigger the magnet the magnet sense did not register and that when the ball gets held it does register - if both conditions aren't met the monkey does not pickup the ball reliably.

Thanks again.
Do you mean the switch that registers when the ball has been dropped? If so, I recall that being an occasional issue on some machines. I can't recall the exact fix, but if you email JJP tech support they should have a solution (may involve bending the wire actuator to provide more clearance).
Great videos! I am actually having an issue after the monkey grabs the ball and drops it behind the castle wall. About half the time it bounces out due to the switch not retracting. Do you think this adjustment on your video may fix that or could it be another issu? Looking forward to additional tweak vids for Woz.
Great overview Daniel! I installed 4.0 and noticed my magnet sense switch was flagged bad. By flipping the sensor it worked "too" well (AKA... was sensing the magnet firing, not the ball arriving), so I also had to move it slightly and now it seems to work as expected and matches the behaviour in your video. Thanks for taking the time to do this!