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Discussion Starter · #1 ·
A strange little case that may have a simple explanation, I think it would have been about eight years ago I purchased a Scalextric set '70' off eBay. There were various factors that made it appear it had never seen use - the general condition of the track, the presence of rubber bands on the Twin Auto-Screams cables and the unopened instructions envelope. There was even a little stand-up Scalextric advertising card in the bottom of the box, too.

The cars (C/81 and C/82 Cooper and Lotus) appeared unused even down to the pickup braids, but the motors in both, despite their visual condition being perfect, were completely dead. All three poles open circuit on both.

Are there any expert ideas on how this would have come about? A set intended for display, or possibly been returned faulty and never sorted out? I can't quite believe the possibility that it might have been bought at great expense, found unserviceable and simply put to one side.

BTW the cars were subsequently given working motors but the duds were kept...

What does the panel think?

Jim
 

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All of the above Jim!

What do you mean by "open circuit on both" for all three poles - a short?

Scalex checked cars before shipping, theoretically, so it may be more oxidation over time, cold solder joints or something of the sort... At least these cars aren't too hard to replace!

Don
 

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Discussion Starter · #3 ·
Hi Don -

Open circuit on both, by which I meant none of the windings were continuous when checked on a multimeter. I've infrequently found motors with one pole down but not all three...and I seem to recall I did re-flow all the solder joints attaching the windings to the commutator, very fiddly job but unfortunately to no avail. That was the point when replacement motors went in them.

I suppose it's also possible that exchange of motors had happened before the set reached me; perhaps I've been overlooking the obvious!

The Twin Auto Screams worked; I can only surmise that it must have been designed by someone who had it in for parents in a big way!!
 

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Polish the coms and see what happens. I have had coms so oxidized they wouldn't read through a multi meter.
 

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It is indeed quite possible that oxidized particles between comm segments may short out the poles... I have seen it before.
 

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Firstly let me say that your Set "70" sounds a beauty Jim, always nice to find sets like that in unused condition. Back to your question about the cars though.

It's actually not too unusual to find cars in that unused but non working condition, well with juniors anyway it seems. I have 4 new condition juniors in my collection that are as you describe ; QUOTE The cars (C/81 and C/82 Cooper and Lotus) appeared unused even down to the pickup braids, but the motors in both, despite their visual condition being perfect, were completely dead.

I know the source and history of these 4 cars I mention very well, and know that these cars have NEVER been used in anyway. They all have sat in storage at the wholesalers for over 40 years though, and I believe that long period laying idle is the start of the problem ... as some have already mentioned, oxidisation of the comm has done the rest.

One other thing to mention is the softening of motor brushes ... they can look fine, but are in actual fact in unservicable condition.
 

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Discussion Starter · #7 ·
Thanks for the suggestions!

It could be a very contentious issue where a case of 'Mint and Unused' actually turns out to mean 'unserviceable'.

I did actually clean the commutators and check the brushes on a known good motor and they were fine (the brushes that is), and as mentioned earlier I'd checked and re-flowed solder joints on the comms. Seems to narrow it down to the armature windings then if I'm not mistaken. I've encountered transformer windings (in old radios) developing breaks especially if powered when damp, so I suppose the same could be the case.

It was and is a beautiful old set - nice way to build a good fast figure-of-8 using as it does a combination of outer and standard curves. For a bit of fine detail the outer curves in the set have a sort of 'long grain' effect on the surface, very different to the rest of my classic track.

Cheers,
Jim
 
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