Welcome to the forum   
Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Share
Options
View
Go to last post in this topic Go to first unread post in this topic
Offline Beavera61  
#1 Posted : 23 April 2025 09:23:26(UTC)
Beavera61

United Kingdom   
Joined: 14/04/2025(UTC)
Posts: 5
Location: England, Witham
I recently bought a Marklin BR120.1 3553 engine, it was listed as not tested. Initial running repairs were completed and a quick test seemed to indicate that this was a runner, however when I first ran it on the track, the train shuddered as it moved and then stopped moving, I then tried to pulse the transformer to change the direction, and it appeared to change but it still refused to move and the lights no longer worked.

Upon first inspection there was no damage to any of the connections and the brushes were making contact with the motor which was able to spin without resistance when the wheels were turned.

I then disassembled the motor to clean the contacts, I noticed that the field magnet surrounding the motor was fairly strong to the point where it would pull the motor off centre, I also inspected the gears to make sure they could freely move and there was no damage to the teeth.

After cleaning the contacts and reinstalled the motor I then applied a voltage across the brush terminals to see if the motor would spin with a directly applied voltage to which it did, however it was not smooth at all and it was almost like a ratchet jittery motion and when I change the voltage, I did not notice a change in speed.

The controller board has not been tested as it is clear that there is some issue with it due to the lights no longer working which are fed by the board and that a directly applied voltage will turn the lights on, I have tried applying a voltage over the terminals where power is supplied to the board with no response.

I would like some help regarding the magnet and its strength to determine if that is what is causing the jittery motion as at this point in time it appears to be the only culprit left in causing the strange operation of the motor it is the first time I have dealt with an arrangement like this as all of the other trains I have use coiled magnets but this one is just a magnet block. I will attach images of the magnet and motor for clarification as well as an image of the controller board.
20250422_113200.jpg20250422_113207.jpg20250422_113255.jpg20250422_113940.jpg
Offline Paul59  
#2 Posted : 23 April 2025 09:55:57(UTC)
Paul59

United Kingdom   
Joined: 25/08/2012(UTC)
Posts: 250
Location: South East
It looks like someone has replaced the wound field magnet with a permanent one thus converting the motor to a DC one.
As it is a 'Five Star Propulsion' loco it would have originally had an AC motor.

Does the motor run by itself when a DC source is applied to the brushes - ie without the connections from the circuit board?

I wonder if it has been converted to digital and that circuit board is actually a decoder.

If that circuit board is the original then it would need an AC motor. However the original 5 star boards would have a couple of little potentiometers on (for setting the max speed and acceleration) and I can't see any on your photograph. You can see them on the line drawing on the cover of the box.

Permanent magnets will pull the armature off centre unless the motor shield is fitted.

Paul
Marklin HO using M track. Now reverted to analogue as I find it has more character and is more fun...... and I understand it!
Offline Beavera61  
#3 Posted : 23 April 2025 11:39:29(UTC)
Beavera61

United Kingdom   
Joined: 14/04/2025(UTC)
Posts: 5
Location: England, Witham
Thank you. My son and I will follow up on your advice.
Offline Beavera61  
#4 Posted : 23 April 2025 12:37:41(UTC)
Beavera61

United Kingdom   
Joined: 14/04/2025(UTC)
Posts: 5
Location: England, Witham
Originally Posted by: Paul59 Go to Quoted Post
It looks like someone has replaced the wound field magnet with a permanent one thus converting the motor to a DC one.
As it is a 'Five Star Propulsion' loco it would have originally had an AC motor.

Does the motor run by itself when a DC source is applied to the brushes - ie without the connections from the circuit board?

I wonder if it has been converted to digital and that circuit board is actually a decoder.

If that circuit board is the original then it would need an AC motor. However the original 5 star boards would have a couple of little potentiometers on (for setting the max speed and acceleration) and I can't see any on your photograph. You can see them on the line drawing on the cover of the box.

Permanent magnets will pull the armature off centre unless the motor shield is fitted.

Paul


My son has carried out the DC test and the motor ran, so it does appear that this was a DC conversion.

So what would be the best way to revert? I have tried sourcing the coil magnet using the article number 231390 but to no avail. The motor armature, E610030, is available.
thanks 1 user liked this useful post by Beavera61
Offline Paul59  
#5 Posted : 23 April 2025 18:58:12(UTC)
Paul59

United Kingdom   
Joined: 25/08/2012(UTC)
Posts: 250
Location: South East
I have tried looking for the wound field magnet for a drum collector motor and not really had any luck.
It's probably a bit harder being UK based unless you want to pay a lot in postage.

Since your motor works ok on DC you could just try to get hold of a cheap and basic decoder which will run in analogue mode such as the Marklin 6090 ones or the ones out of the 60760 kit.
You might find that the decoder in your photos still works. Someone on here who knows more about digital than me might be able to tell you what it is and how it should be wired.
Most if not all of the Marklin decoders will work in analogue mode - they usually automatically detect it.

What I have done on a couple of locos where a previous owner had put in a permanent magnet is to fit a Roco 89940 reverser. This is a small circuit board that rectifies the AC to DC and feeds it to the motor. It has a little relay in it that reverses the polarity in response to the over voltage pulse from the Marklin controller. Roco used to fit them to their analogue locos that were sold to be used on the Marklin system.

Paul
Marklin HO using M track. Now reverted to analogue as I find it has more character and is more fun...... and I understand it!
thanks 1 user liked this useful post by Paul59
Offline marklinist5999  
#6 Posted : 23 April 2025 22:08:04(UTC)
marklinist5999

United States   
Joined: 10/02/2021(UTC)
Posts: 3,864
Location: Michigan, Troy
It's a five pole armature. Didn't all of the analog five Star locos have a magnet instead of a wound field coil? I know they have variable minimum and maximum speed and acceleration and braking delay pots. This would be an easy digital conversion.
Offline H0  
#7 Posted : 24 April 2025 09:13:51(UTC)
H0


Joined: 16/02/2004(UTC)
Posts: 15,432
Location: DE-NW
Originally Posted by: marklinist5999 Go to Quoted Post
It's a five pole armature. Didn't all of the analog five Star locos have a magnet instead of a wound field coil? I know they have variable minimum and maximum speed and acceleration and braking delay pots. This would be an easy digital conversion.
All "five star" locos were analogue and had field coils. The 35xx five-pole armature was different from the five-pole armatures of later digital locomotives.
I cannot tell from the photo if this is still the original 35xx armature or a modern digital type.

Looks as if the loco had been converted with a permanent field magnet and a decoder, maybe ESU.
When buying a new decoder, it could be a good idea to make the full conversion with 60941 motor parts. The 35xx armature requires different decoder settings and it can take time to find them.
Regards
Tom
---
"In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
UserPostedImage
thanks 1 user liked this useful post by H0
Offline Beavera61  
#8 Posted : 26 April 2025 16:48:21(UTC)
Beavera61

United Kingdom   
Joined: 14/04/2025(UTC)
Posts: 5
Location: England, Witham
Hi,

Thank you for the input. Further research would seem to indicate that this appears to be the original five pole armature.

As I run analogue, I was hoping to retro fit a field coil magnet which I believe was similar to the original set up of the earlier 3553 (this had a three star armature). The other issue would be finding the original control board.

I'll check with a couple of the sellers that I have sourced parts from previously.
thanks 1 user liked this useful post by Beavera61
Offline Dave Banks  
#9 Posted : 26 April 2025 22:32:07(UTC)
Dave Banks

Australia   
Joined: 08/03/2006(UTC)
Posts: 1,041
Location: Gold Coast, Australia.
This is one of my BR120 locomotives I converted many years ago from delta to digital with a Marklin high propulsion kit being the 5-pole digital armature, brushplate with screws & brushes & permanent magnet. At the time only the Marklin #6090 decoder was the one available to me & still has never let me down. If I had to do it all over again now I would have fitted it with an ESU lokpilot decoder:

[img]UserPostedImage[/img]
D.A.Banks
thanks 1 user liked this useful post by Dave Banks
Offline mvd71  
#10 Posted : 27 April 2025 11:29:52(UTC)
mvd71

New Zealand   
Joined: 09/08/2008(UTC)
Posts: 1,916
Location: Auckland,
ESU Lokpilot decoder is the way to go. Will work on analogue and digital with good performance.
thanks 1 user liked this useful post by mvd71
Users browsing this topic
Guest
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

| Powered by YAF.NET | YAF.NET © 2003-2025, Yet Another Forum.NET
This page was generated in 0.463 seconds.