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Offline DasBert33  
#1 Posted : 05 October 2019 17:20:53(UTC)
DasBert33


Joined: 21/01/2004(UTC)
Posts: 1,164
Location: Mortsel, Belgium
Hi all,

I need some technical advice. My nephew (10) gave me his defective startup loco, he says it 'started to smoke from the bottom'.

The loco in question is a NMBS series 96 steamer, technically similar to br74 36740.

Upon opening the loco I noticed the light conductor near the decoder had melted, and the decoder itself had some components desoldered. So it became very hot (hence the smoke). When I connect the motor to a DC supply I see it draws ~1.5A at 15V, which is way too much. If I let it run for a while the wires start to smoke from the heat. It does run however, and it appears to work, although sometimes it has a tendency to be jerky (sudden, momentary speed increases). But the general speed seems rather constant and all wheel turn ok.

So the motor/mechanics are defective somehow, and the original decoder is probably friend because of this.

Is there anything I can do to fix it or to verify what is wrong? Any ideas on the cause or recommendations on what to do? Oil on the brushes is one thing I am thinking about (it does not appear overoiled). Is this a common issue with this type of cheap locos?

Luckily I gave my nephew a good old heavy metal BR81 last year. That one will never break down at least.

Bert

Offline RayF  
#2 Posted : 05 October 2019 19:41:45(UTC)
RayF

Gibraltar   
Joined: 14/03/2005(UTC)
Posts: 15,440
Location: Gibraltar, Europe
Originally Posted by: DasBert33 Go to Quoted Post
Hi all,

I need some technical advice. My nephew (10) gave me his defective startup loco, he says it 'started to smoke from the bottom'.

The loco in question is a NMBS series 96 steamer, technically similar to br74 36740.

Upon opening the loco I noticed the light conductor near the decoder had melted, and the decoder itself had some components desoldered. So it became very hot (hence the smoke). When I connect the motor to a DC supply I see it draws ~1.5A at 15V, which is way too much. If I let it run for a while the wires start to smoke from the heat. It does run however, and it appears to work, although sometimes it has a tendency to be jerky (sudden, momentary speed increases). But the general speed seems rather constant and all wheel turn ok.

So the motor/mechanics are defective somehow, and the original decoder is probably friend because of this.

Is there anything I can do to fix it or to verify what is wrong? Any ideas on the cause or recommendations on what to do? Oil on the brushes is one thing I am thinking about (it does not appear overoiled). Is this a common issue with this type of cheap locos?

Luckily I gave my nephew a good old heavy metal BR81 last year. That one will never break down at least.

Bert



The motors for these locos are very cheap. I would get a replacement fitted. It also sounds like you will need a new decoder.

While you're at it, with the motor removed, check the chassis for smooth operation when pushed along by hand.

Once the decoder and motor are replaced the loco should be good as new.

Ray
Mostly Marklin.Selection of different eras and European railways
Small C track layout, control by MS2, 100+ trains but run 4-5 at a time.
Offline Rwill  
#3 Posted : 05 October 2019 21:42:35(UTC)
Rwill

United Kingdom   
Joined: 04/05/2015(UTC)
Posts: 547
Location: England, London
My opinion which will not be well received is to pick up from Ebay etc from one of these guys that break down start sets a brand new lok from start set 29074 for about 90 Euros complete with warranty etc
Offline DasBert33  
#4 Posted : 06 October 2019 10:51:31(UTC)
DasBert33


Joined: 21/01/2004(UTC)
Posts: 1,164
Location: Mortsel, Belgium
Dismantled the loco some more this morning. Was able to test the motor seperately without the chassis. The motor is definitely defective, it now draws 2A when running without any load on a DC supply. It does not seem oily, so I have no clue what is wrong.

Repairing it will not be worth it sadly, some of the plastic threaded bodyparts that mate with the screws were broken off, the lightconductor in the back has melted away, the decoder is probably dead (although i will resolder and test it anyway), and some bodyparts were already missing after playing. These costs will be bigger than buying a new or 2nd hand loco. And it will be very difficult if not impossible to put it back together even if I would have suitable replacement parts.

As a replacement I am now looking at the older T12 style locos, such as 3103. For my 10year old nephew the sturdiness & repairability of these older models are much more important than detailing anyway. The metal couplers will be a lot better than the flimsy NEM pockets on the new model that had a tendancy to hang down and touch the pukos, especially after playing (& crashing) with the loco. I had to replace the short couplers by simple couplerhooks for this reason.

And not to forget the one screw on the top for easy maintenance.

Bert
thanks 1 user liked this useful post by DasBert33
Offline RayF  
#5 Posted : 06 October 2019 11:46:15(UTC)
RayF

Gibraltar   
Joined: 14/03/2005(UTC)
Posts: 15,440
Location: Gibraltar, Europe
That's probably the best decision seeing as the way you describe it the loco is a bit of a wreck! Smile

If the loco is indeed for a 10 year old then I would recommend going for the basic 3095 instead of the rarer 3103, unless there is a reason that the loco must be green. The 3095 is easier to find at a cheaper price than the more unusual derivatives.

If you need the loco to be digital you can try to find a 30951 which comes with a delta decoder from factory. It is the later type of delta with switch-able light in digital operation. There's also a blue version which came in starter sets 29175/6.

https://www.ebay.co.uk/i...bae74:g:pwEAAOSw1mZdlLDI
Ray
Mostly Marklin.Selection of different eras and European railways
Small C track layout, control by MS2, 100+ trains but run 4-5 at a time.
Offline tonyfh  
#6 Posted : 06 October 2019 13:16:46(UTC)
tonyfh


Joined: 17/04/2004(UTC)
Posts: 91
Location: Netherlands
Hello Bert,

In case you are looking for a "new" locomotive, next saturday october 12 is a large swapmeet in Houten, Netherlands, https://www.modelspoorbeurs.nl , sorry but I could not find an english page.
I have already found nice loks from my youth for a very fair price and mother M still carries a lot of spares in their warehouse.
Lots and lots of new and used stuff in all conditions and also one or two sellers specialised in spareparts.
So if you have the opportunity.....

Greetings, Tony.
Offline DasBert33  
#7 Posted : 06 October 2019 15:42:29(UTC)
DasBert33


Joined: 21/01/2004(UTC)
Posts: 1,164
Location: Mortsel, Belgium
Thanks Ray for the tip on the blue one. It's a good candidate. Only reason for 3103 is that is looks less common than the usual black/red steamers.

Thanks Tony for the Houten tip. I have been going there sometimes for a few years already, but since recently I don't have a car anymore (my wife has a Fiat500, but can you call that a car? ;) ) it is more difficult to get there. You can find some bargains in Houten indeed, if you look properly.

I have removed the motor, the fried electronics and the melted parts. It has just enough working screws left to hold it together. The loco is now demoted to a plain wagon. My nephew can now push it around himself or use it behind another loco with a motor for easy double heading operation.

All in all I think the loco survived around 3 years, which is really disappointing compared to how indistructable older M locos are that do not come from China.

Bert
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