Toy Taxi - Strange behavior I haven't seen before

[GHold]

Greetings all! I have been roaming the forums for a while now, and finally decided to create an account so I can post and join the discussions. Great resource, thank you all for being here.

I am working at a site that has (2) Toy Taxi crane machines, and one of them is exhibiting behavior I have not seen before. It moves well, and all the directional switches are fine with regards to its positioning, and knowing it has reached the back/side of the unit, etc. When you drop the claw in most places, it works fine. But any time you drop it within the last 2-3 inches at the back of the machine, regardless of it's horizontal position, the unit will "lock up" when it retracts from the grab attempt.

As long as you keep the claw away from the back area (rear wall), it has no issues. I took off the cover, and it appears to pull the claw "up" further than it should, and locks the unit up. If I nudge it or pull the unit forward a half inch or so, it relaxes and goes back to normal operation, returning to home and dropping whatever it picked up. 

Mechanically, it's action is identical when it's slightly more towards the front of the machine, so I'm not sure why the last couple of inches towards the back would cause different behavior. It's the same drop distance, same switch triggers, etc. But for some reason when it retracts to the top it keeps pulling in / turning that motor and jams the entire process up.

*Second Item (unsure if it's related) - The claw coil is constantly very hot, even when the machine is just sitting idle. It functions normally, opening and closing the claw when it should, but is definitely hot non-stop. The unit in question is set to "play until you win" mode, if that matters.

[gumball guy]

8 hours ago, GHold said:

Greetings all! I have been roaming the forums for a while now, and finally decided to create an account so I can post and join the discussions. Great resource, thank you all for being here.

I am working at a site that has (2) Toy Taxi crane machines, and one of them is exhibiting behavior I have not seen before. It moves well, and all the directional switches are fine with regards to its positioning, and knowing it has reached the back/side of the unit, etc. When you drop the claw in most places, it works fine. But any time you drop it within the last 2-3 inches at the back of the machine, regardless of it's horizontal position, the unit will "lock up" when it retracts from the grab attempt.

As long as you keep the claw away from the back area (rear wall), it has no issues. I took off the cover, and it appears to pull the claw "up" further than it should, and locks the unit up. If I nudge it or pull the unit forward a half inch or so, it relaxes and goes back to normal operation, returning to home and dropping whatever it picked up. 

Mechanically, it's action is identical when it's slightly more towards the front of the machine, so I'm not sure why the last couple of inches towards the back would cause different behavior. It's the same drop distance, same switch triggers, etc. But for some reason when it retracts to the top it keeps pulling in / turning that motor and jams the entire process up.

*Second Item (unsure if it's related) - The claw coil is constantly very hot, even when the machine is just sitting idle. It functions normally, opening and closing the claw when it should, but is definitely hot non-stop. The unit in question is set to "play until you win" mode, if that matters.

There are several things that could be causing these issues. They could be related or they could be independent of each other. I would suggest swapping out the power supply with one you know works. A failing power supply could lead to both of these problems so I would try that first and see if it resolves. The coil should not be energized when the game is sitting idle so that is another reason I am suspicious of the power supply. If the power supply is not the issue then it could be broken wire causing the claw operation to fail intermittently when the wiring harness gets stretched out toward the back of the machine. The problem would be specifically in the wires that go to that upward limit switch that stops the claw when it reaches the top and begins it's trip to the chute. A continuity test on those wires, as you manually move the crane head into the problem area, should tell you if it's a broken wire.

The real head scratcher is the hot coil. Coils can get hot after multiple plays but if the machine is sitting idle for 20 minutes and the coil is still hot then there is a problem. I would definitely try another coil just to make sure that the original one isn't faulty and getting ultra hot during play. The thing that doesn't make sense is if the coil is getting constant voltage (and it shouldn't be) then it would try to close. I guess it could be getting just enough voltage to warm it up and not close but again that's indicative of a probable power supply issue or board malfunction.

Unfortunately it is usually trial and error when it comes to diagnosing some of these issues.  

[GHold]

Thank you for the info and suggestions, I appreciate it. I did some more digging and realized that I had not checked the battery. Guessing this might be part of my issue.

 

[Vendo Mike]

Eek.. you'll need to carefully remove, clean, check the traces for opens and reinstall IC23.  That's assuming it's still good.  You may end up replacing it.

[GHold]

I swapped the board with our other Toy Taxi, same issue with the lockup, so the battery corrosion isn't the issue there. I'll look into the continuity and power supply issues next. I can't imagine that corrosion is good though. 

I definitely need to clean that up, and likely socket/replace that chip. Check traces, etc.

Edited October 30, 2023 by GHold

[GHold]

We may have a winner on the retraction issue. There was definitely a continuity drop off on a connection from one of the related switches when the unit was in the rear area. After a bunch of testing and manipulating the wiring, it became a permanent continuity issue. I pulled the gantry and took a close look, found a broken wire that was probably hanging on by a thread previously.

[gumball guy]

2 hours ago, GHold said:

We may have a winner on the retraction issue. There was definitely a continuity drop off on a connection from one of the related switches when the unit was in the rear area. After a bunch of testing and manipulating the wiring, it became a permanent continuity issue. I pulled the gantry and took a close look, found a broken wire that was probably hanging on by a thread previously.

Glad you found it. Those zip ties are a common breaking point on these wire harnesses. Thanks for letting us know what the culprit was. 

[GHold]

I still have to figure out why the claw coil is always hot. As noted above, it's strange it would be extremely hot when it's not pulling in and at rest, and still appear to function normally. I generally only see solenoids hot like that when they're locking on (or in heavy repeat use). Idle heat without pulling is weird.

[gumball guy]

6 hours ago, GHold said:

I still have to figure out why the claw coil is always hot. As noted above, it's strange it would be extremely hot when it's not pulling in and at rest, and still appear to function normally. I generally only see solenoids hot like that when they're locking on (or in heavy repeat use). Idle heat without pulling is weird.

If the coil and power supply are fine maybe that board corrosion is coming into play? Not sure if you checked the coil when you switched the boards out to see if it was still getting warm.  Again, trial and error.