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Discussion Starter · #1 ·
Hi,
I am experiencing the weirdest problem I have ever had with a slot car.This Holden goes like the clappers but has an intermittent braking problem.Sometimes(of course when you least expect it) it refuses to slow down for the corner down when you release the controller trigger after you have accelerated down the straight.This oddity happens on both lanes
The problem does nor occur with my other cars although I do not discount coincidence
I use Parma 45 Ohm controllers with the brake connected.I have tried new controllers but the problem still occurs.I have fitted a new motor to the Holden,but no luck.
It has these new Scaley slimline jobbies.(I learnt a trick in the process:how to make a standard pinion fit the narrower shaft, but that is a story on its own)
The only thing I can think of, is that front of, the car lifts under acceleration and the braids no longer make contact thus negating the effect of the controller brake.
I have tried adding weight to the front but perhaps not enough.

I will be grateful for any pointers as this Aussie job(tough as it is) will not be able to take off the table like a jet for too much longer before having to go the panelbeaters.

Cheers and regards from a cold Johannesburg
Bryam
 

Prof I T
Joined
11,098 Posts
hi
dynamic brakes work by sending a reverse current to the motor when the throttle is released,cordless drills and the like operate in the same way,you can see the brush gear spark when this happens.

So i would say that this reverse current is sometimes not getting to the motor, usual culprit is the throttle not zeroing properly.

I had this very same problem when i first got into digital and it cost me a brand new Ferrari F1 car as it flew off the table into a brick wall.
 

Registered
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913 Posts
Are you using a powerbase, if so what make of track system, as it might be something in there
or
have you wired your track and controller like club tracks using 3 pin plugs etc.

If you are using a standard track system, ie scalextric, scx ninco, then try changing the power base track section as it seems to me you have eliminated the car and controller side of things.
 

Circuit Owner
Joined
5,905 Posts
Hi Beneke,

You say this does not happen with other cars - this suggests your power base, controller and track are OK.

You have tried a different motor in the Holden and that did not cure the problem - suggesting the motor is OK.

Scalextric slimline motors are notorious for bad braking by the way but your inconsistent problem suggests something else.

Braking in analogue works by channelling the electricity generated by the coasting motor back to the motor to effectively try to power itself in reverse - the motor resists and slows down.

In order for this to work the circuit from motor through to controller has to be complete.

I would expect the braids to make better contact with an unpowered car as weight will be transferred towards the front of the car.

What this all points to is a problem between the motor and the braids (not a track problem as your other cars brake consistently).

I am wondering if you have a fracture in your wiring or a dry soldered joint between the motor and the braids that is put under strain when the car's weight transfers forward.

Suggestion? - Replace the wiring between your braids and your motor and make sure you solder well - and see if this cures the problem.

You haven't said if this car has lights. I assume it doesn't but that might be another area to explore if wire replacement doesn't cure the problem.
 

Ray
Joined
1,093 Posts
Hi (Apart fron getting a Ford sorry I am a Ford fan) check the braid contact on the track sometimes if on of the braids is not contacting the track you haved no brakes.

Ray
 

Nobby Berkshire
Joined
2,015 Posts
Just add more weight if you think it's lifting up?

If that makes no difference then check for wires touching and just accept it's the ff motor. It's famed for having rubbish brakes.

Otherwise, enjoy the novel fun of having an unpredictable car. It makes slotracing exciting to have some variation.
 

Registered
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Discussion Starter · #7 ·
Hi Guys,

Thanks for the pointers.Definitely a poor contact problem between car and rails.I think I have found the root.
I rewired the car and it misbehaved on the very first lap thereafter.I thought sod this and fitted a magnet just behind the guide blade and voila!... no aeroplane anymore.
By pure chance I put my Scaley Maserati on the track( I know I did say other cars did not misbehave but I did not test all of them) and lo and behold exactly the same symptom in exactly the the spot.
The spot is where the Classic track changes to a short section of Sport track just before a bend to accomadate a lapcounter.The Sport track rails are lower and narower than the Classic track.I have had problems before with this section of track not providing good contact.

The other commonality is that these cars would not trigger the switch of the lapcounter,which to me points to the fact that the guide is lifting out of the slot and hence the lack of electrical continuity.
Perhaps the cold weather also has something to do with it

My plan is to replace the Sport lapcounter with a modified Classic lapcounter and so elimate the Sport section.To me the Classic track is better anyway as it provides more superior grip

Never to old to learn!
PS:Oh and by the way the five Fords(Sierra's and Mondeo's) I have, just roll over on their backs around corners and sing Waltzing Mathilda at you at the mere sniff of power .

Thanks and best regards

Cheers
Bryan
 

Registered
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Almost definitely it's the braid not being in contact with the track, it can often be the little bumps that develop over time in Sport track that can cause this, I've also got some SPort track where the rail is low. I have the same problem with some cars on my Sport track in the garage, it's usually caused by bumpy track.
 
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