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Offline JohnjeanB  
#1 Posted : 16 March 2020 14:56:20(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hello Marklin fans

Yesterday I had the sad surprise of my Märklin BR 58 ref 37589 to have its decoder in short circuit while moving slowly and alone.
Here is the picture of the culprit
UserPostedImage
The culprit is circled in red.

I tested the motor and its ohmic resistance is very low ( 2 to 3 Ohms) but when connected to a DC transfo it turns without a noise and no smell

My questions:
- do you know this component ?
- how can I get a replacement?

Thanks for any advice
Cheers
Jean
My lay-out videos
latest vid
humping yard
Offline hxmiesa  
#2 Posted : 16 March 2020 15:11:58(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 2,865
Location: Spain
Originally Posted by: JohnjeanB Go to Quoted Post

I tested the motor and its ohmic resistance is very low ( 2 to 3 Ohms) but when connected to a DC transfo it turns without a noise and no smell

Yes; Only when a higher voltage is applied and the thing starts to turn, will it induce a magnetic field which offers resistance to the electricity.
For a motor, that is normal.

Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
thanks 1 user liked this useful post by hxmiesa
Offline bph  
#3 Posted : 16 March 2020 16:22:34(UTC)
bph

Norway   
Joined: 04/08/2018(UTC)
Posts: 129
Originally Posted by: JohnjeanB Go to Quoted Post
Hello Marklin fans

Yesterday I had the sad surprise of my Märklin BR 58 ref 37589 to have its decoder in short circuit while moving slowly and alone.

My questions:
- do you know this component ?
- how can I get a replacement?

Thanks for any advice
Cheers
Jean


Sorry to hear
do want to replace only the fried chip or the whole decoder ?
in theory you should be able to get a new mSD3 decoder and load the decoder project from https://www.maerklin.de/en/products/details/article/37587 (I have 37589, and I believe they are quite similar.)


Offline jvuye  
#4 Posted : 16 March 2020 18:46:45(UTC)
jvuye

Belgium   
Joined: 01/03/2008(UTC)
Posts: 2,813
Location: South Western France
Originally Posted by: hxmiesa Go to Quoted Post
Originally Posted by: JohnjeanB Go to Quoted Post

I tested the motor and its ohmic resistance is very low ( 2 to 3 Ohms) but when connected to a DC transfo it turns without a noise and no smell

Yes; Only when a higher voltage is applied and the thing starts to turn, will it induce a magnetic field which offers resistance to the electricity.
For a motor, that is normal.



2 to 3 ohms seems a bit low if you ask me ...Confused
Besides , this is a permanent magnet motor, and, stictly speaking the magnetic field is always present Wink
What offer "resistance " is the opposite tension generated by the rotation of the motor in that field ( in French force contre électro-motrice ou réaction d'induit)
Back to your BR 58: the main failure mechanism of these can motors is carbon residue from the brushes shorting the blades of the commutator, and thus also shorting the decoder output.
Yours looks like the typical outcome
The motor part number is E189104, and it sells for € 25.00 , available from Märklin .
Personally I would try to take the brushes out and try to check how the commutator's surface looks, but I cannot offer any advice on how to get to them as I never worked on this type of loco/motor in the past.
Cheers
Jacques
Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success!
thanks 2 users liked this useful post by jvuye
Offline JohnjeanB  
#5 Posted : 16 March 2020 19:32:21(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi
Thank for all your answers and questions.

Originally Posted by: hxmiesa Go to Quoted Post

Yes; Only when a higher voltage is applied and the thing starts to turn, will it induce a magnetic field which offers resistance to the electricity.
For a motor, that is normal.


I hope you are correct but frankly the value seems very low to me. Only one way to verify if you are correct: measure the motor's current when running with 8 volts (a medium/high speed). IMO current should not be more than 100 mA .

Originally Posted by: bph Go to Quoted Post

Do want to replace only the fried chip or the whole decoder ?
in theory you should be able to get a new mSD3 decoder and load the decoder project from https://www.maerklin.de/en/products/details/article/37587 (I have 37589, and I believe they are quite similar.)



Hi BPH, I am checking if by replacing a cheap MOSfet component I can save the decoder. I have done this already on my coal system (Grossbekohlungsanlage)
Otherwise I have a project to program a mSD3 and provided by Märklin.

Originally Posted by: jvuye Go to Quoted Post

2 to 3 ohms seems a bit low if you ask me ...Confused
Besides , this is a permanent magnet motor, and, stictly speaking the magnetic field is always present Wink
What offer "resistance " is the opposite tension generated by the rotation of the motor in that field ( in French force contre électro-motrice ou réaction d'induit)
Back to your BR 58: the main failure mechanism of these can motors is carbon residue from the brushes shorting the blades of the commutator, and thus also shorting the decoder output.
Yours looks like the typical outcome
The motor part number is E189104, and it sells for € 25.00 , available from Märklin .
Personally I would try to take the brushes out and try to check how the commutator's surface looks, but I cannot offer any advice on how to get to them as I never worked on this type of loco/motor in the past.

Hi Jacques
I quite agree with you and I will compare with a similar Märklin motor. On the other hand the motor runs so smoothly and quietly. Anyway I have to check. Otherwise it is additional 25€ plus shipment to add to a 74€ mSD3. I must measure the current absorbed on DC 8 Volts. It must be in the range of 100 mA

My dream wish: the motor is OK and I can find an SMD component to replace the one with a "beer muscle"BigGrin
On the other hand I don't want to risk burning a new mSD3 because of motor overcurrent

Thanks again for your help. It is great
Jean
My lay-out videos
latest vid
humping yard
Offline AshleyH  
#6 Posted : 16 March 2020 20:41:24(UTC)
AshleyH

United Kingdom   
Joined: 15/02/2008(UTC)
Posts: 669
Location: Bournemouth, Dorset
As you have said, the melted component on your sound decoder is a Mosfet. If you can source one and have the soldering skills then that should restore your decoder.
However, there are two Mosfets on your decoder, one for forward and one for reverse. I have had this problem on an LGB decoder, the symptom being that the loco would only run in reverse.
Have you tried reversing the direction of the loco? It might prove the motor is OK and the decoder repairable by the replacement of the melted Mosfet.
Offline JohnjeanB  
#7 Posted : 16 March 2020 23:01:00(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi Ashley

This is a very interesting information. Thanks
I have not tried yet because the decoder is shorting the power, so I need first to remove the suspected IC and then test what you say.
I noticed there are 2 identical components: the fried one and its immediate neighbor which seem to confirm what you write.
Thanks again

Jean
My lay-out videos
latest vid
humping yard
Offline hxmiesa  
#8 Posted : 17 March 2020 11:38:31(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 2,865
Location: Spain
Originally Posted by: JohnjeanB Go to Quoted Post
I tested the motor and its ohmic resistance is very low ( 2 to 3 Ohms) but when connected to a DC transfo it turns without a noise and no smell

By all means if you suspect the resistance to be too low; As you are able to run the motor from another DC source AND you have a tester, then you can easily measure the amps going through it when running. That would tell you directly if it is consuming too much energy.

Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
Offline JohnjeanB  
#9 Posted : 17 March 2020 15:27:46(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi Ashley
Yes and today I removed the fried component UP 3A3 ( from LG I guess) now the decoder provides sound OK but the
Motor is not driven
At least it means the mother board is OK
Cheers
Jean
My lay-out videos
latest vid
humping yard
Offline AshleyH  
#10 Posted : 18 March 2020 17:05:07(UTC)
AshleyH

United Kingdom   
Joined: 15/02/2008(UTC)
Posts: 669
Location: Bournemouth, Dorset
I think that is mostly good news Jean, the sound part is the expensive part!

I think there is a good chance that, if you cannot find the two Mosfets as components, you may be able to use them from a standard non sound decoder, if you can find one with the same components.

Of course, I think it is going to very hard to find any of this now in the current situation across the world.
Take care and keep well.
Offline JohnjeanB  
#11 Posted : 18 March 2020 23:00:20(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi Ashley

Thank for your kind wishes. Keep away from harm.
The bad {technical} side is I measured the motor resistance and found 2.3 Ohm while on a similar motor on a Märklin larger engine (the 39241) it was 46 Ohms so the motor even if it runs is to be changed.
Take care
Jean
My lay-out videos
latest vid
humping yard
thanks 1 user liked this useful post by JohnjeanB
Offline JohnjeanB  
#12 Posted : 19 March 2020 18:04:41(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi

Here is the last picture of the needed component
UserPostedImage
I need help to find these 8 pin SMD components marked UP 3A3 in red circle.
Any information would be much appreciated
Thanks
Jran
My lay-out videos
latest vid
humping yard
Offline ktsolias  
#13 Posted : 19 March 2020 21:13:45(UTC)
ktsolias

Greece   
Joined: 01/05/2016(UTC)
Posts: 446
Location: Athens
Hi

My opinion is that the best think is to buy a new decoder....

Costas
Offline kiwiAlan  
#14 Posted : 20 March 2020 06:01:56(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,932
Location: ENGLAND, Didcot
Originally Posted by: JohnjeanB Go to Quoted Post

I need help to find these 8 pin SMD components marked UP 3A3 in red circle.
Any information would be much appreciated
Thanks
Jran


Hmm, as it appears (from your thread) that it drives the motor, my bet is that they are power MOSFETs, two to a chip, with the two chips making a full bridge configuration. As it appears there are two identical chips, then the two FETs inside will be opposite polarities.

A quick search doesn't show any obvious candidates, and I suspect it may require a more investigative approach to the schematic to get a replacement.
Offline AshleyH  
#15 Posted : 20 March 2020 12:35:30(UTC)
AshleyH

United Kingdom   
Joined: 15/02/2008(UTC)
Posts: 669
Location: Bournemouth, Dorset
Another option, if the Mosfets prove difficult or impossible to source, would be to leave the existing decoder in place for the sound effects, but fit a second basic decoder for motor control only. The wiring would need some thought, so that the motor is only connected to the motor outputs on the basic decoder, but both decoders need the track input. Probably best to get a simple wired 8 pin decoder, as there is no second socket.

The arrangement would be similar to using a non-sound loco with one of Marklin’s sound coaches that they produced a few years back. I have one, so I need to read up on how to get the two on the same address. Not easy with MFX. But everything is solvable with a little ingenuity.
Online Purellum  
#16 Posted : 20 March 2020 13:37:00(UTC)
Purellum

Denmark   
Joined: 08/11/2005(UTC)
Posts: 3,347
Location: Mullerup, 4200 Slagelse
Cool

Originally Posted by: AshleyH Go to Quoted Post
fit a second basic decoder for motor control only


Great idea BigGrin

Now, why didn't I think of that.......... Blushing LOL Laugh

Per.

Cool

If you can dream it, you can do it!

I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.

In case this is not legally possible:
I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

UserPostedImage
Offline JohnjeanB  
#17 Posted : 20 March 2020 18:08:16(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 706
Location: Paris, France
Hi Costas, Alan, Ashley & forum friends
Thank you for your ideas:
@Costas: yes probably getting a new sound decoder and a new motor would be the safe way forward (not the cheapest nor a daring solution though
@Alan: finding a replacement for this component would be my preferred solution because I would learn 2 things: get a replacement for those power components that are likely to burn (also the rectifier bridge) and the other thing would be to get myself a SMD soldering system (SMD Lötstation) and learn how to use it. But so far no indication of the missing component.
@Ashley: yes it would be a great idea but there is no much room in my BR 58 to have an additional decoder (mLD3). Driving both in parallel would be made by creating a traction on my CS2 and Rocrail so there would be no problem there.
Stay away from harm & take care
Jean
My lay-out videos
latest vid
humping yard
Offline kiwiAlan  
#18 Posted : 22 March 2020 01:41:00(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,932
Location: ENGLAND, Didcot
Originally Posted by: JohnjeanB Go to Quoted Post
...and the other thing would be to get myself a SMD soldering system (SMD Lötstation) and learn how to use it. But so far no indication of the missing component.


One way to do this is to use a halogen lamp to heat all the pins at once, which is almost a necessity when removing components. There is a video on Youtube on doing this. You could then do the same to fit the new component.


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