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Discussion Starter · #1 ·
Hi guys
I have a new Dome Judd "Le Mans" in yellow, blue and green (SCX61450) who after a few great laps started to act like the motor was getting just 2-3volts, or just doing what looks like 2-3000 RPM: it does not pick up RPM anymore, it just "paces" around slowly at full controller speed. Tried all lanes, with other controllers, checked the guide etc etc but it runs very very slowly. Any suggestions on what could be wrong? The car was bought on the internet, which is the only way I can get cars and makes it impractical to demand some kind of substitution.
Thanks
Edo
 

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I don't have that car, but on my SCX rally cars the contact from the motor to the copper strips in the chassis has been poor sometimes. Once I made sure they made good contact the cars performed significantly better.
Not sure if this solves the problem, but it's worth checking...
 

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In this situation, I would run power directly from a transformer straight to the motor terminals, via wires. I have a separate transformer, but you could use a battery or run a couple of wires from the power rails if you don't have one available.

If the motor now runs normally, you KNOW that the problem must be somewhere between the motor terminals and the power rails in the track and can work your way back along the contact points in the car until you discover where the power loss is and then make the contact good again.

If direct power straight to the motor terminals makes no difference, then the problem is the motor itself.
 

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My experience with these is that it may well be the connection between the motor and the connecting strips on the chassis. Because the motor swivels you often need to bend the connectors to maintain a good contact. The early evidence of this may be loosing power on certain sections of track with a different camber.

The second weak point is the connection between the chassis connecting strips and the top of the braids. Again this is sprung and judicious bending may be necessary to get the right reliable connection.

I would also just check that the magnet isn't too low and contacting the track.

I've found one of these motors very susceptible to too much lubrication and WD40. This ran very slowly and very hot until it burnt off in a cloud of smoke. A good clean out with lighter fuel was suggested to me to try to slove this problem. Don't know if this is a good idea????
 

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Sounds like another one bites the dust !! (Queen playing loudly in the back ground)
Here in SEQ the SCX motors have a high rate of attrition. Almost every racer I know has had at least one failure, some, two or more this year. It usually happens within a half hour or so of being new. Older motors seem to make it past this threshold and then live long and happy lives

Not too sure why but it usually amounts to a failure of the comutator of some kind. Motors run slow, emit a bit of a smell, sometimes smoke. Dismantling reveals the brittle collar around the base of the com disintegrates, taking winding pigtails with it!

I have rewound several now for friends and have had to use mabuchi coms on some to replace the damaged originals. One thing though, its an opportunity to put a few less windings of a little thicker wire on. Then stand back and watch peoples faces !

Another SCX trait is for the TV supressor to short out internally and eventually burn out, litterally! This is sometimes preceeded by a period of poor to slow running. Try cutting the supressor off first.

a note to all when using ebay, caveat emptor!
 

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Discussion Starter · #6 ·
Thanks guys
I'll let you know what is happening with the my Dome Judd motor as soon as I have time to go through your suggestions. As usual I get very valuable help on this forum.
Best
Edo
 

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Discussion Starter · #8 ·
Hi guys
after trying all your suggestions and having shown the Dome Judd to experts like Thomas and SwissRacer I can confirm that the motor is dead.
Worst is that there is no OEM SCX motor available from the usually very helpful British stores nor there is in Italy where I got it.
Apparently SCX does not send original Dome Judd motors to dealers and the Turbo-Turbo Plus are not interchangeable.
I am left with the possibility of putting in a Slot.it V12 motor (now THAT is a company that produces reliable, great, well done, out of the box perfect fast cars and accessories!!!).
Frankly I am very disappointed at SCX and will not purchase their cars anymore.
S...t happens but lack of service and spare parts is, to me, inexcusable.
Best regards
Edo
 

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Graham Windle
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Edo if you send me the motor or the full car I will repair it for you . scx motors are very tunable and easily repaired or rewound Email or pm me and Ill give you my address .
 

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Discussion Starter · #11 ·
Thanks Misguided
Thanks Graham
I was going to contact you but in the meantime the Italian store has promised to exchange the car (less body) with a new one.
Best regards
Edo
 

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Discussion Starter · #13 ·
Graham
in fact I was dying to send you the dead SCX motor and have a rewound speed monster come out of your lab. I am very interested in your motor services.
Questions:
my track power is 3-15 volts 10 Amp, will your rewound motors suck more amp of what is available?
Do you work on other motors like slot.it or others?
Do you revise, clean, fix and renew old 1960's Mabuchi's 26D and 16D ?
Thanks
Best regards
Edo
You might want to see my track here:
http://www.slotforum.com/forums/index.php?showtopic=2932
http://www.slotforum.com/forums/index.php?showtopic=3032
 
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