# aurora tjet testing via battery



## crosmans (Aug 26, 2011)

Hi,

I want to test a Aurora Tjet car but don't have a track. If I simply use a 9 volt battery and touch the contacts, shouldn't the motor run? I know it won't be full speed.


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## Bubba 123 (Sep 10, 2010)

crosmans said:


> Hi,
> 
> I want to test a Aurora Tjet car but don't have a track. If I simply use a 9 volt battery and touch the contacts, shouldn't the motor run? I know it won't be full speed.


yup, should run impressively.. can check 4 binding problems that way 2 :thumbsup:


Bubba 123 :wave:


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## Jisp (Oct 19, 2008)

Yup, what Bubba said. It's a really common practice among slotters for testing and tweaking cars. You can ramp it up a notch by grabbing a 9V battery connector, the type that pushes onto the battery and has two wires trailing off to the side. Attach a light duty shielded alligator clip to each wire and it makes connecting to the car a breeze. Oh, and don't toss nearly exhausted 9V batteries. When they are run right down they still tick a motor over nice and slowly - perfect for running new brushes in. Have fun.

Cheers,
Michael. :thumbsup:


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## crosmans (Aug 26, 2011)

Gulp. Then it doesn't work , even though it is in minty condition. I should have mentioned that I've tried this and nothing happened. The chassis is similar to the pic attached. Had this vehicle on a tyco set, running, when I was little. I've got a couple of Carrera track sets, but they are at a bigger scale. tjets dont look easily serviceable, maybe that metal band needs to be gently pried off, may have to research.


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## Jisp (Oct 19, 2008)

Do you know for a fact that the battery is not completely flat? If you hold the chassis lightly by either side do the rear wheels turn freely? They are reasonably easily serviced but no point pullin' it to pieces without clearing a few things up first.....

Cheers,
Michael.


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## old blue (May 4, 2007)

Don't give up! Everyone is here to help. Pry off the metal band and look inside. Chances are you are missing a brush or something. Could be the magnets are wrong. If you want to post a pic you will get plenty of help.

Old Blue


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## Boosted-Z71 (Nov 26, 2007)

Unless there are parts missing, more than likely it just needs a good cleaning and the electricals, brushes & armature polished up. 

Boosted


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## wyatt641 (Jan 14, 2012)

t jets are easily serviceable..learned all i needed here from these folks..let them walk you through it..or send it to me and i will disassemble clean and replace parts for you and send back..
dave


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## Shadowracer (Sep 11, 2004)

Ok...first thing: Check that each pickup shoe has a brush spring. You can do this just by looking at it. If there's no spring it could bugger up contact.

If there's springs, lay out a white rag or towel to work over.

The next step is to take a small screwdriver and gently pry the copper clip off the chassis. Then lift the gear plate off the chassis. Keep an eye on the gear that lays directly under the clip. It slips on and off by design and will likely fall off. Dont lose it. 

Check the comm brushes. That's the two little round pill-like things that are set in the two holes on the inside bottom of the chassis. If either of those holes is empty, then there's your problem. Sometimes they will come out and roll around loose, and sometimes..well, someone just forgot to put one back.

If they are both there, go back to the gear plate and check the bottom of the armature for wear and gunk. Clean that up as best you can.

Take a piece of paper and lay it on the table, then take each of those motor brushes, put them down so that the side that touches the armature is face down touching the paper. Put your finger over it and just rub the brush around on the paper. You're basically buffing the crud off the brush.

Crud on old brushes and the armature bottom is pretty normal when a car has been sitting. 

I bet dollars to donuts those two steps will solve your problem.


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## cwbam (Feb 8, 2010)

many old pancakes like 22-30 volts DC (like an old HP printer power supply)
MORE Power!!!!!!

9 volt batteries can go quiet quickly and don't have lots of amps
strong magnets can also also require more power to get the arm moving


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## Rich Dumas (Sep 3, 2008)

I use old 9 volt batteries to test my cars after I am done cleaning and oiling them. They last a long time, even though they were not fresh to start with. It might be better to use a power supply or a rechargable battery if you want to lap gears.
If the rear axle turns smoothly the drivetrain must not be bound up. Possibly there is not enough motor brush tension, either because the brushes are worn out or the springs are bent. After you remove the gear plate/armature assembly check to be sure that the tops of the motor brushes are at least a 1/16th of an inch above the floor of the chassis. Once you have the gear plate off you might as well clean the commutator with contact cleaner or metal polish. Don't use anything that will scratch the commutator. After you reassemble the car put a tiny drop of oil on the lower end of the armature shaft. You can do the holes in the gear plate, the idler shaft, the end of the cluster gear shaft and the axle holes as well, but that first one is critical with T-Jets.
It is rare to have an electrical problem with the armature itself.


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## crosmans (Aug 26, 2011)

Thanks. Will look into this in more depth shortly. Following up on the replies:
- The 9v battery was fresh and full strength.
- The motor doesn't turn at all when using the 9v.
- The rear wheel and gears turn OK (I took off the body).

I'm into RC electric boats so I know some about DC motors and all.


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