# tyco lighted chassis US1 wire question Help!



## PAPSTISY (Nov 23, 2017)

I'm new to the boards. I found some interesting posts. I'm also new to the hobby and love it. Anyway, I have a Tyco US1 lighted chassis. This chassis is suppose to have a light that flashes as it's a fire truck. On the good truck I have can anyone tell me what the one wire shown grounded to the rear axle is? Maybe a resister, flasher or breaker? I will be needing one of these for the bad truck I'm fixing. I believe it's whats used to actually make the light flash. As I put a meter to it and needle wagged. After I find out what it's called I'm wondering if they can be bought? As you can tell I'm a newbie trying to do things on my own which is dangerous I know. But still fun! Any help as to what it is/called? Or where I could possible find the same thing would be great. I look forward to your feedback.


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## Rich Dumas (Sep 3, 2008)

I have never seen one of those, here are pictures from the Model Motorist site.



















I could not resist unscrunching your picture.


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## Rich Dumas (Sep 3, 2008)

Maybe you have the wrecker?


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## alpink (Aug 22, 2010)

you will notice there are two wires going to the rear axle.
one directly from a pickup shoe .....
the other rides on a cam on the other side of the rear axle and can only touch the axle when in a certain position on the cam, completing an electrical circuit, to light the bulb.
the other wire to the bulb probably goes through a resistor to the other pickup shoe.
so, yes, both wires have to be properly in place. 
if one is missing or broken, find a piece of piano wire ( 1/24 racers use them a lot) that is similar in diameter and stiffness to replace with.
this will require minimal soldering skills


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## PAPSTISY (Nov 23, 2017)

Ha you guys! Thanks for your posts. I have both wrecker and firetruck that will need to have light replaced. The pic I posted is the wrecker. I posted that because it was not missing any of the piano wires. The one piano wire has a little round solder dot. Which can be seen on the fire truck and wrecker in above pics. I'm wondering what that is on the piano wire? any idea? If I need to replace wire on cam side which needs to be done on the fire truck I have, will the wire need that solder dot.
Im hoping that was place on wire to make a proper bend to wire and thats all. 
The suggestion to use piano wire is awesome! I would have never ever thought of that! I'm going to mic. and purchase the correct size if that dot is placed on wire just to make bend. Any ideas or thoughts as to what that is?


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## peejay75 (Dec 18, 2018)

PAPSTISY,

Did you ever get your lighting issues taken care of? I've recently gotten back into US-1/US1 trucks, picked up the fire engine, and the light works, but not in reverse! (Had a problem where the rear axle would bind would going into reverse, lubricating the motor and gears seem to have fixed that).

While I'm at it, any tips on how to disassemble the chassis to get at the motor for servicing???


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## peejay75 (Dec 18, 2018)

Update...

Er, maybe the light isn't "supposed" to come on in reverse? (Saw a youtube video of an operator backing the fire truck into the station, and I'm sure I saw the light(s) flash a few times).

Well, now I'm thinking any lighting in reverse is due to "residual" touching of the cam/wire, just by chance of it being in the closed circuit position from when it was going forward...Was able to get mine to light (once) for a brief second when in reverse. Looks like by design, the tension spring that turns the shaft disengages when in reverse, and therefore no turning shaft means no cam to open/close the light circuit, as well as activate the plunger for the bell...maybe?


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## MrMajestical (May 14, 2019)

There are two hard wires that are basically the "flasher" for the lamp. There is a cam on the axle that breaks the contact and provides the ground for the lamp. Pretty ingenious! 
As far as I can tell, the lamp does not work in reverse. I had bought a 3911 from eBay, and have a dedicated terminal track for testing chassis, it was in reverse, so initially I thought the lamp was burnt out.
Flipped to forward and it worked.
I had bought several trucks that "clicked" when ran, and when switched direction, they would stop running. One was a wrecker, so not wanting to break anything on it I left it alone.
I had a green dump that did the same thing, and it was much easier ripping it apart. What I found was the worm gear on the armature has small cracks, and they were just enough to lock the gears up. 
I then actually ended up taking several lower end trucks apart till I found a good gear to put in the Wrecker. I was dismayed about how many trucks had the cracked gear, and just stopped looking for them in lieu of having no operable trucks.


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## MrMajestical (May 14, 2019)

peejay75 said:


> PAPSTISY,
> 
> Did you ever get your lighting issues taken care of? I've recently gotten back into US-1/US1 trucks, picked up the fire engine, and the light works, but not in reverse! (Had a problem where the rear axle would bind would going into reverse, lubricating the motor and gears seem to have fixed that).
> 
> While I'm at it, any tips on how to disassemble the chassis to get at the motor for servicing???


You take the screw out of the bottom. If I remember right that plastic part that holds the light clips in where the weight goes in the back. Then fish the hard wires out. I had one stripped to the base chassis, I just can't remember all the details. But once you get all that out of the way, it is just the same as a typical chassis.


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