Lightbars are NOT smoke machines!!!

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lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
It all started about fifteen minutes ago. I've been testing each of my lightbars today, to maintain quality. All was well, until the unexpected (and terrifying) happened.


I have an older MX7000 and I hooked it up. Everything worked as it should up until I got to the red rotator wire. When I connected the rotator wire, it got extremely hot, the inner two rotators lit dimly and spun VERY slowly, and a jet of smoke came out of the bar. I've seen short-outs before, but absolutely NOTHING that smoked this much.


I have two questions for you all: Where are common short-out places in MX7000's, and what could possibly be smoking so much?
 

JohnMarcson

Administrator
May 7, 2010
10,991
Northwest Ohio
Usually smoking is caused by something like plastic or dirt getting heated by a short.
 
May 21, 2010
1,591
Berlin, MI, 48002
You might have a bare part of the red wire touching the frame up inside the bar someplace.


Another common short-out is the wires getting smashed underneath the decks & aluminum plates on the older ones.


All the smoke is due to all of the arc-ing that went on in the bar. They usually smoke pretty good when they arc for long enough.


Hopefully you didn't fry your rotator motors (you 'probably' didn't). Those I'm sure will smoke when shorted, but I dunno exactly how much.
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
ChargerLighting said:
You might have a bare part of the red wire touching the frame up inside the bar someplace.
Another common short-out is the wires getting smashed underneath the decks & aluminum plates on the older ones.


All the smoke is due to all of the arc-ing that went on in the bar. They usually smoke pretty good when they arc for long enough.


Hopefully you didn't fry your rotator motors (you 'probably' didn't). Those I'm sure will smoke when shorted, but I dunno exactly how much.
Yeah, the plates make it IMPOSSIBLE to get to the motors. I have no idea how to disassemble this thing, because it's so different compared to my newer MX7000. Do you know how to get the plates and rotators off/out? I doubt I fried my motors, though, because the two inner motors spun and there was no power to the outer ones.


The jet of smoke was seriously smoke-machine quality, which makes the whole thing even more unsettling.
 
May 21, 2010
1,591
Berlin, MI, 48002
To see alot of the wires, you just have to pull the 4 long screws out (with a 1/4" socket) & you can pull the whole thing off the frame & you'll see the majority of the wires on the underside.


If there's nothing wrong there, you can pull just the black rotator deck off. To do that you have to pull the snap rings off the 2 rotators & take the reflectors off. Then you have to remove the 4 nuts next to the long screws - I believe those are 9mm.
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
ChargerLighting said:
To see alot of the wires, you just have to pull the 4 long screws out (with a 1/4" socket) & you can pull the whole thing off the frame & you'll see the majority of the wires on the underside.
If there's nothing wrong there, you can pull just the black rotator deck off. To do that you have to pull the snap rings off the 2 rotators & take the reflectors off. Then you have to remove the 4 nuts next to the long screws - I believe those are 9mm.
Alright, thanks. I always seem to have problems taking off the snap rings on the rotators. I'm sure I'll be able to find the problem sometime, but it sure will be a pain. And the smell is terrible!
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
So… I opened the bar up, and I found what the problem was. Luckily, I didn't have to mess with the rotators, but, WOW, that wire really did fry. What I'm thinking that happened is that the red wire touched the frame in some small place on the frame, then heated up, allowing the insulation to melt/fry off the entire wire, stripping it of insulation and letting it hit the frame. About 3/4 of the insulation melted off, and the other 1/4 is blackened and brittle. Now I'm just debating whether or not to just wrap it in electrical tape and forget about it, or go and buy some new wire.


Here's a pic for reference; this used to be a green and red wire.


ai54.tinypic.com_jqkgw3.jpg
 

JohnMarcson

Administrator
May 7, 2010
10,991
Northwest Ohio
New wire. There very well could be other issues with it.
 

EVModules

Member
May 16, 2010
865
Deer Park, WA
Complete re-wire. You do not want to take the chance of it frying up again.


The smoke came from the insulation. Next time, use a fuse even if it's just for testing!!!
 

grfd711

Member
Jun 23, 2010
1,546
Sherwood, AR
Wire will be inexpensive compared to the cost of replacing multiple components of the bar or the entire bar itself. As Sean said, don't forget the fuses.
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
EVModules said:
Complete re-wire. You do not want to take the chance of it frying up again.

The smoke came from the insulation. Next time, use a fuse even if it's just for testing!!!
Any idea what it should be fused to? I'm taking a guess at like 20 amps, but I could be wrong…
 

EVModules

Member
May 16, 2010
865
Deer Park, WA
Use 15a & 30a Circuit breakers made for automotive for testing purposes. Test smaller circuits on the 15, multiple rotators on the 30. It's just wired inline of the circuit if you're bench testing it.
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
ChargerLighting said:
To see alot of the wires, you just have to pull the 4 long screws out (with a 1/4" socket) & you can pull the whole thing off the frame & you'll see the majority of the wires on the underside.
If there's nothing wrong there, you can pull just the black rotator deck off. To do that you have to pull the snap rings off the 2 rotators & take the reflectors off. Then you have to remove the 4 nuts next to the long screws - I believe those are 9mm.
Any tips or a howto on to take the snaprings off the rotators? I don't especially want to force them off, so I figured I should ask.
 

CrownVic97

Member
May 21, 2010
3,352
Hazen, ND
lotsofbars said:
Any tips or a howto on to take the snaprings off the rotators? I don't especially want to force them off, so I figured I should ask.

A pair of snap ring pliers from your local hardware store should do the trick. They look like this:


[Broken External Image]:http://www.northerntool.com/images/product/images/558644_lg.jpg


There are many brands, but you want the ones that you squeeze together and the prongs move outward. Hope this helps a bit :) .
 

lotsofbars

Member
Jul 20, 2010
1,999
NYC, New York
CrownVic97 said:
A pair of snap ring pliers from your local hardware store should do the trick. They look like this:


[Broken External Image]:http://www.northerntool.com/images/product/images/558644_lg.jpg


There are many brands, but you want the ones that you squeeze together and the prongs move outward. Hope this helps a bit :) .
Ahahaha, wow, how did I not know those existed? thanks a lot!
 

CrownVic97

Member
May 21, 2010
3,352
Hazen, ND
I agree with Sean. Better to minimize the risk of putting a scratch in your MX rotators using curved over straight pliers.


You're welcome, BTW, lotsofbars :cool: .
 

toon80

Member
May 24, 2010
2,489
Laval, Canada
lotsofbars said:
Ahahaha, wow, how did I not know those existed? thanks a lot!

That particular pliers model is the exact same I bough for the exact same purpose: removing snap ring from a MX7000. Worked fine for me. As for the direction of opening, you'll notice a red tab on it. Flick it and the pliers open when you squeeze. Flick it again and they closes when you squeeze.
 

Uman18

Member
Jun 2, 2010
423
Port Hueneme, CA
Ive taken apart 100's of bars for scrap, some look good on the outside but the internal wire harness is sometimes brittle that the insulation just breaks off and the wire is exposed. Seams like its mostly on Code 3 bars in my opinion. I once had a C3 360 bar I had polished and looked almost new, but when i opened it up the arrowstik harness had shorted and melted the harness to the other lights. It was a mess to re-wire, I just scrapped it for parts.
 
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