Recently, I began tinkering with my old AFX non Magnatraction and Magnatraction cars. Being around since these cars were introduced I pretty much have experience in all the methods/tricks in getting a car to run well.

But with some of these 36 year old cars I just can't get them to produce the power they should.

A complete cleaning, tuning and oiling has some cars still unable to make full power. With everything seeming to be at its best why do some cars not respond?

Jim Norton
Huntsville, AL

Since I didn't stay at a Holiday Inn Express last night I'll take a stab that the armature is faulty in some way or the magnets just don't have any "oomph" any more. Try any metering of the arm?

Everything turns freely without much effort?

An expert, I'm not, but I would look in the hidden areas for an answer. Pop off the shoes and clean the hook where they make contacct with the rivited plate on the chassis. Then I would clean up the inside of the shoe hanger area (between the plastic and the plate where the shoes hook on). This is the weakest area of electrical continuity and I still get surprised at just how little a piece of dirt can stop a car dead in it's tracks.

Weak magnets can affect performance, as well as an arm that has been cooked. Check the ohms on the arm and see if it measures the same all the way around.

Any bit of rust and grime on the axles is going to slow you down too.. These are the few tricks I've picked up. I'm sure others will have alot more to add to the list..

my guess is it;s weak magnets

I'll second the cleaning of the hook on the pickup shoes. Ohm out armatures and make sure brushes are cleaned on both faces on 600 grit paper and clean commutator of armature. That's good for starters, let us know....

Jim,

How about shoe tuning/contact patches?

I have always found the AFX pancakes to be quite sensitive in this area. We're talkin' night and day difference ....sometimes.

How about crusty springs under the brushes.... *ugh*

Brush tension?

Do any need a bump start to get going? If so it's a broken armature wire.

One thing I run across on an Afx car that's been sitting for years is compressed springs, both pickup and comm. Using a an XT's spring as a model, I compare them and tweak the Afx so it's close in appearance. Also, clean out the motor chamber......That can make a difference. And an oiling in the usual spots should help things along.

Thanks for the suggestions.

I had a sneaky suspicion it would be the armature or the magnets as the chassis was cleaned and has been well maintained.

I have a magnet in my pit box that has lost its magnetic strength so much that it is now a piece of metal only. Maybe the same in the cars?

How do you test the armature with a meter? Is there any method short of "feel" for evaluating the magnet strength?

Thanks again,

Jim Norton
Huntsville, AL

From the bottom of the arm you'll see 3 copper "pie" shaped sections. Touch one probe to two different sections and get a reading on an ohm meter. Work your way around the arm until you have covered all three sections. The ohms should be pretty close all the way around. If one is way lower one it's messed up. I'm not sure what AFX arms should ohm out at so someone else will have to fill in the rest.. Or you can ohm check a good runner to see where it measures and compare to your duds..

Another thing to check is to see if the windings are loose or unraveled.

Several links that may help. A cheap way to test magnet strength, listing of AFX armatures, and using an ohmeter. If you hit the previous button on the netfixer page, you can find a pretty detailed step by step guide to putting a tjet chassis together. The AFX chassis will be similar. Hope the links work.



http://www.netfixer.net/slots/arm.html
http://www.slotmonsters.com/slot-car-afx-magna-traction-pancake-motor-armatures.ashx
http://www.slotmonsters.com/slot-car-testing-magnet-strength.ashx

how about, their old........get some autoworld cars, lmao...........I'm wearing a heat resistant suit, so no burning will do you guys any good.

LOL again

Well Jim..did any of the most excellent advice from the experts round here revive any of your old magnatractions? Inquiring minds would like to know.

Well Jim..did any of the most excellent advice from the experts round here revive any of your old magnatractions? Inquiring minds would like to know.


Yes Jim, we need the rest of the story! :) rr

First.....I need to purchase an ohm meter.

Does anybody have suggestions for a readily available one good for slots?

Jim Norton
Huntsville, AL

An el cheapo from Radio Shack or your local hardware store should work just fine.

I recently had to replace the one my son decided to abuse so I went with a Cen Tech for $8 shipped off an epay seller. Works just fine for playing with toy cars. Harbor Freight has the same thing for $5 but I don't know what their shipping is.

Jim, so far the advice referring to cleaning is the place to start. You really have to spend a little time on the connection points of the pickup system, there are some tiny little nooks that tarnish up real easy, killing the flow of power. From there you want to inspect the arm to make sure it isnt cooked, but replacing some consumable parts with affordable JL/XT replacements would be the next step. Unless your old springs (pickup and brush) are shiny and fresh looking, scrap em. You can get a cheap lot of new JL/XT parts on Evilbay, and while your at it grab some motor magnets too. Magnets do lose pull over time (30+ years will do it) and the XT mags are stronger anyway. These simple, cheap upgrades oughtta perk your chassis right up.

Jim- I would like to add one more item on your checklist. Since magnatractions use a combination of brush tabs and springs, you have to make sure that there is adequate pressure for the brushes on the commutator. After you have completed cleaning and re-assembly, try to position the car upside down against the power source. You will need the body off so you can touch the front of the pick ups against the transformer leads.
Then using a screwdriver push down on the tabs one at a time and see if there is any change to the RPM's. If it is significant enough, you may have to bend the tabs up into the brush tube slightly to get better pressure. I tune/de-tune most of my magnatraction/non mags and t-jets using this method.
Jim

As noted, one area of concern on an older car is springs. While one can find NOS Aurora springs or use AW Xtraction units, I have found that Dr. Oogan's srings to be worth the price. He originally made T-Jet P/U shoe springs but has expanded his line to include AFX P/U and bruch springs. His ebay handle is given below.

http://shop.ebay.com/merchant/dr_oogan_W0QQ_nkwZQQ_armrsZ1QQ_fromZQQ_mdoZ

He lists on the bay from time to time. He also maintains a web site which is listed below.

http://www.freewebs.com/oogan/

You can email him and order up some springs. I have been buying chassis and gear plates with arms on the bay and building them up into runners. These springs are better than NOS. :thumbsup::thumbsup:

Russ the Hutt :drunk::hat::freak::dude::tongue:

how about, their old........get some autoworld cars, lmao...........I'm wearing a heat resistant suit, so no burning will do you guys any good.

LOL again

Actually SND, that ain't a bad idea. I just bought a bunch of MT's. They run, but not very good. So, I bought 6 XT's from Mr_Aurora (wink, wink) to use. I plan on working on the MT chassis but, I wanted to run the bodies, NOW. I was torn between getting them on the track right away and rebuilding them myself with pride so, I settled for both.

Spent some time this weekend on the car not making power. It is a Porsche 917 that was my first AFX car. Over time, it lost its original AFX chassis and now has a 33 year old Magnatraction Chassis.

Anyway, it would not generate high rpms despite every trick in my bag. So, I tried the mentioned tips in this thread.

The Method:

1) I cleaned the area where the pickup shoes attached to the chassis. No change in performance.

2) I examined the comm brushes and springs. The springs looked compressed and dirty. I replaced both with new from a Johnny Lightning chassis. The result was no change.

3) I then felt the motor was bad. I then replaced the 33 year old motor with a better looking equivilant from the parts box. No difference

4) I then went back to the Johnny Lightning chassis. I lifted the motor from it and installed it in the 917's chassis. The car then screamed! I was shocked. What a great motor Johnny Lightning has! Might be my fastest AFX car.

Conclusion:

Both 33 year old motors were bad. These were red armatures. One thing I did notice on both of these was soiled or blackened spots on the wires of the armature.

Question:

What makes an armature go bad? Were these spots on the wires the culprit? Any insight appreciated.

Jim Norton
Huntsville, AL

What color were the poles on the arms you replaced?

What makes an armature go bad?

Either heat or a bad upbringing.

I'd go with - heat.

I second the heat.

Both bad armatures were as follows:

1) Red with red wires
2) Red with copper wires

Jim Norton
Huntsville, AL