# Aristo Heavyweights - adding polyfuses to protect against internal light base shorts



## Rayman4449 (Jan 2, 2008)

A week or so ago, I had a second Aristocraft Heavyweight almost go up in smoke. (i.e. wiring completely melt into a pile of copper and plastic) The cause: The light bulb base hot glued to the top of the roof works loose from the glue and shorts across the two power wires running along the length of the car top. The first time I had this happen, the car in the course of 5 seconds started billowing smoke from the time I turned the switch to the time I could turn it off. I had to completely disassemble the entire car and rewire & replace the on/off switch. 

In the cars I've been able to get the roofs off, I've added a bunch of hot glue to the bases to ensure they don't work loose. However, some roofs are near impossible to get off even trying to work the retaining tabs back with a long screw driver. SO, I've decided to go ahead and add resettable polyfuses to each of the power wires going into the bottom of the car at each truck. 

Before: 









After: 









Tested them installed (they are .65 amp (1.3amp trip)) and the fuses work fine and should protect against any future light base shorts. 

Source for the fuses: http://www.allelectronics.com/make-a-store/item/RXE-065/RESETTABLE-CIRCUIT-PROTECTOR-0.65-1.3-AMP/-/1.html 


Raymond


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## Greg Elmassian (Jan 3, 2008)

*RE: Aristo Heavyweights - adding polyfuses to protect against internal light base shorts*

Raymond, dumb question: 

If the bulbs make heat, which softens the hot melt glue (surprised?), why not affix the sockets with something more heat-resistant? 

Regards, Greg


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## Rayman4449 (Jan 2, 2008)

*RE: Aristo Heavyweights - adding polyfuses to protect against internal light base shorts*

Hey Greg, 

Not a dumb question, they just don't get THAT hot. My lights are regulated to a max of 12v on my Challenger's 11 car consist. For the Hudon's 4 car I'm using 28v bulbs and even they don't get that hot running at 24v. (because of the amperage bulb I selected) The problem isn't that the hot glue is softening it's mainly that 1) there wasn't enough applied (where it wasn't wrapping around to actually hold it down... it was just stuck to it) and I'm guessing maybe 2) that the glue wasn't hot enough went applied so as not to provide a sufficient bond. I've found that if you don't have your hot glue really hot (above a certain temp) when bonding, your parts will eventually fall away (i.e. not adhere like they should) as some of these lights have done. With them doing so many so fast I bet the glue gun temps drop below this critical temperature. To put it another way, if you've ever heated hot glue up to the point where it's soft, you first notice that it still is tacky (stuck) and is not easy to move, second when you do the hot glue stretches and stays adhered to the object you've stuck it to. In the cases where I've had the bayonet bases come loose there is no stretching or anything it's hard and flat. This is the big reason why I think the original hot glue temps are insufficient and the small bit of expansion and contraction of the bayonet base metal (from the lights being turned on and off over time) eventually works it loose of it's insufficient bond to the glue. 

If they were getting so hot that they would be melting the glue they would all be falling out, which they aren't. And those cars that I have been able to get the tops off and reglue, I can assure you, they aren't going anywhere. So in short, more hot glue was simply the quickest and easiest solution to the problem instead of trying to come up with something different and the adding of polyfuses which is the topic of the thread is the final insurance that I will never for any reason ever have to worry that another one of my Heavyweight's internal wiring will ever go up in smoke again. 


Raymond


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