[Scaretactics]

Hello! Recently I opened up my Dead Eye Drake to do some repairs, and I came across this horrific wiring in the head. The LED lights are wired to the mouth motor. The power coming from the board to the mouth comes from the orange and brown thicker wires that are together. You may be able to see the lone resistor coming off one of the motor terminals off to the side. There also appears to be residue on the red wire attached to the resistor and the other white wire, making me think it was glued up on the plastic support. Here is the weird part: The lights in the eyes and the mouth movement all work fully. The only thing that's off is that the mouth movement seems to be extra powerful. Has anyone ever worked on one of these and know how it's supposed to go? Any electronics guys out there know what would make the most sense? I don't want to short anything out, seeing as these guys are so hard to come by. Thank you in advance for any advice!!!

 

[J-Man]

If everything works, I wouldn't mess with it. Is the power supply the correct voltage? Higher voltage would definitely cause the mouth to seem more powerful.

 

[Scaretactics]

If everything works, I wouldn't mess with it. Is the power supply the correct voltage? Higher voltage would definitely cause the mouth to seem more powerful.

Yes, I am currently using the power supply included in the box with it. The more I look at it, the more it doesn't make sense- if the resistor were to connect to any of the wires that are loosely hanging on to the other resistor, it would simply make 2 electrical paths of equal resistance leading to the same place. Maybe the resistor was originally connected to the two motor terminals, and movement of the head over time caused the partially connected resistor to shift that way?

It may be a bad idea to connect a resistor like that in parallel to a motor, warn me before I try it! 😜

 

[J-Man]

Yeah I wouldn't connect any resistors to the motor. It's hard to make out exactly what is going on in your photo. Two resistors of equal value that are wired in parallel would effectively double the potential current that can pass thru them safely. For example, if a device draws 1/2 watt and the resistors are only rated for 1/4 watt, then using two resistors in parallel will allow 1/2 watt of current to the device. When a resistor is undersized for the task, it will burn up.

 

[Scaretactics]

For example, if a device draws 1/2 watt and the resistors are only rated for 1/4 watt, then using two resistors in parallel will allow 1/2 watt of current to the device. When a resistor is undersized for the task, it will burn up.

Very good to know. I understand, it's hard to tell at all how it is wired together. I will do some further investigation. It sounds like the resistors are meant for the lights, not the actual mouth movement. That would honestly make more sense. I wonder if they wired it wrong from factory.

 

[Scaretactics]

Here's a better shot of the entire head. It appears that the white and red/white thin wire go to the left eye, and the red and black thin wire go to the right eye. Black wire from the right eye and white wire from the left eye attach to one motor terminal, and red wire from the right goes onto the connected resistor and so does the red/white wire from the left. I believe I may have solved my own issue. It only makes sense that the red/white wire from the left eye should go on it's own resistor, which should be the lone one off to the top. Since both resistors end up at the same point, does that make sense?

 

[Scaretactics]

Here is an even better shot of how the wiring is laid out:

 

[J-Man]

I still can't make out where the second resistor goes and yes, resistors are definitely needed for LED's. So it appears that both LED's are connected to one resistor, which is fine.

 

[13doctorwho]

It looks like you have two motors. The one for the jaw and one for eye movement. If it works I'm not clear on why you want to make changes. Do the eyes light alright? Do they move alright? The motor for the jaw movement looks like it has a gear box. The speed the mouth moves and the FORCE are different. Higher or lower voltage won't effect the force it closes with, just the speed.

 

[Scaretactics]

It looks like you have two motors. The one for the jaw and one for eye movement. If it works I'm not clear on why you want to make changes. Do the eyes light alright? Do they move alright? The motor for the jaw movement looks like it has a gear box. The speed the mouth moves and the FORCE are different. Higher or lower voltage won't effect the force it closes with, just the speed.

I was incorrect on assuming there was a resistor dedicated to the mouth motor, and I realize now the spring tension on the mouth needs adjustment. If you look closely in some of the pictures, you will see a resistor that is connected only to one terminal of the motor, and nothing else. This is why I was so confused, and because I assumed there was a resistor that was supposed to be on the motor for the mouth movement, I then automatically assumed that the spring tension was fine. I realize now that it is most likely meant for an LED in the eye, and that both LED's should have their own respective resistors. As of now, they are both wired to the one resistor, which I believe to be a mistake from factory.

 

[J-Man]

Higher or lower voltage won't effect the force it closes with, just the speed.

Higher voltage to a DC motor does indeed increase the torque (force) as well as the speed. Look at the specs on any servo using 4.8v compared to using 6v.

 

[13doctorwho]

It's actually the current that increases torque.

 

[J-Man]

It's actually the current that increases torque.

Not to get nitpicky but it's the increase in voltage that increases the current.

 

[Scaretactics]

I did some further investigation and I realized that the resistor that is on the LEDs is a different color code than the one that is off to the side! I left the eye wiring alone and added some solder to solidify the connection. The LED one is Brown-Green-Brown-Gold (1.5 kiloohms) , and the other one appears to be Yellow-Blue-Brown-Gold (460 ohms). I may have written in the color code backwards, but if my calculations are correct, the resistance difference between these two is HUGE. This further disproves my theory that each LED has it's own respective resistor. The lone resistor also appears different, with one side of its wire coated in a brown insulation.

Any guesses to what is going on here????

I still feel that this resistor is purposeful and not a mistake, since this is, well, a Halloween prop, and is made very cheaply. I feel like something like this would not be a factory error.

 

[J-Man]

Well you're right on the calculation of the Yellow-Blue-Brown resistor = 460 ohms but the Brown-Green-Brown is 150 ohms, not 1.5K. The Gold band is the tolerance, 5%.
The 460 ohm would be suitable for connecting both LED's in SERIES.
The 150 ohm appears to have the LED's connected PARALLEL. That's about right depending on the supply voltage.

 

[Scaretactics]

Well you're right on the calculation of the Yellow-Blue-Brown resistor = 460 ohms but the Brown-Green-Brown is 150 ohms, not 1.5K. The Gold band is the tolerance, 5%.
The 460 ohm would be suitable for connecting both LED's in SERIES.
The 150 ohm appears to have the LED's connected PARALLEL. That's about right depending on the supply voltage.

That's right, I wrote it down the wrong way. Thank you so much for the info! Maybe they intended to install the LEDs in series, but switched to parallel after? Who knows.