R3725 BR51XX Motor Failure

[Brew Man]

Good luck with the search, it's not Hornby's strong suit.

[What About The Bee]

Brew Man

Does your board look like this X7507 from Peters Spares?

Bee

[What About The Bee]

With the photos approved, I do believe they are the same board.

R0 and C1 are the RC network to suppress noise, the RC network that appears on many a model. Not sure what L2 & L3 are.

Is the black on the back of your board an applied material? That's where the Peters Spares board has the nomenclature.

Bee

Edit: are L2 & L3 resistors for Led 2 and Led 3?

[Fishmanoz]

I’m betting L2 and L3 are further suppression components in series with the motor connections.

Then for fault-finding, you might remove C in case it has failed short circuit then bridge across each of L2 and L3 in turn to see if either have gone open circuit.

But I’m doing best guessing on this.

[Brew Man]

With the photos approved, I do believe they are the same board.

R0 and C1 are the RC network to suppress noise, the RC network that appears on many a model. Not sure what L2 & L3 are.

Is the black on the back of your board an applied material? That's where the Peters Spares board has the nomenclature.

Bee

Edit: are L2 & L3 resistors for Led 2 and Led 3?

 

 

Bee, for the last time, there is NO nomenclature on the PCB - either on the front OR on the back. Furthermore there is NO applied material on either side. The ID on Peter's Spares picture is on the front of the board, not the back along with the pin designations etc. His product is clearly produced by a different manufacturer.

L2 and L3 are coils as Fishy indicates, L being the common and accepted SI system for labelling inductors.

[Brew Man]

I’m betting L2 and L3 are further suppression components in series with the motor connections.

Then for fault-finding, you might remove C in case it has failed short circuit then bridge across each of L2 and L3 in turn to see if either have gone open circuit.

But I’m doing best guessing on this.

 

 

I'm inclined to agree with you, Fishy. I said earlier that I thought the components were speed conditioners, but have re-considered and think too that they are there for noise suppression.

I will be checking all four components later when I can get to my meter. Replacing them is out of the question as they are so small. I am happy to wait for a new PCB to arrive.

 

 

[Fishmanoz]

I think I’d be trying to open the C and short the Ls and run just like the direct pickups to motor solution. You’d soon see if any effect on motor running.

[Brew Man]

Yes, I could try that while I'm waiting for the new PCB to arrive.

[Brew Man]

Just as a follow-up to this thread, My new PCB and blanking plug arrived and were fitted yesterday. Normal operation has been resumed. Interestingly the noise suppression components on the new set are on the blanking plate and not the socket PCB. What does that tell us? It tells us that they are only relevant to DC operation. Also interesting is that the new PCB comes with ID as per Bee's picture. That should please him. When I get a minute I will compare component measurements with those the old PCB to see if the failed component can be identified.

[What About The Bee]

Hello Brew Man

I am glad to see that resolution to the problem is moving along smartly. That is satisfying to me.

I seem to have somehow upset you, in my determination to see the solution. In that I find no satisfaction. If I have somehow offended you, my apologies. I do not wish ill will or hard feelings between us.

What does moving the suppression components tell me? That Hornby recognized their initial solution didn't need a revision, it needed a redesign. Instead of a duff locomotive, a duff blanking plate. Far cheaper in returns and repairs to simply offer a relatively inexpensive blanking plate replacement instead of an expensive locomotive replacement.

Would someone mind explaining to me why the suppression components are even needed anymore? It is clear from Teditor and yourself that the locomotives function without them. The tiny fields generated by modern motors are not likely to interfere much with RF transmissions. Witness the bluetooth receiver decoders, which would be in close proximity to the motor, albeit at a different frequency.

Are the suppression components just an artifact of obsolete regulations?

Bee

[Brew Man]

Hello Bee

No, you haven't offended or upset me, I was just getting a bit exasperated over the nomenclature thing. I am sure we can happily move on.

I'm sure you are right about moving the suppression components off the PCB and onto the blanking plate, makes replacement far easier. I think another reason might be that having them in circuit on a DCC loco could interfere with the track signals to that loco.

As for the requirement for them in the first place, you are probably correct also, and in my experience not all locos have them by any means. So I suppose it begs the question of why include them in some but not others? Having said that, I have an Oxford Rail Adams Radial that also had such components installed on the decoder PCB so I decided to swap it for a normal PCB with straight connections and on attempting to run the loco its decoder immediately cooked. thinking_face

You said: 'Are the suppression components just an artifact of obsolete regulations?' This is almost undoubtedly correct. In relation to the suppression capacitors that we see strapped across loco motors, it is likely they are there because the Electro-Magnetic Compliance requirement tells them they must be, even though as we know, interference to or from such motors is highly unlikely. Maybe the bodies that review EMC requirements think it better to er on the safe side. Or maybe it has just simply slipped through the net.

[dBerriff]

Amateur radio enthusiasts might care about suppression. It depends what band they operate in, and how close they are to the emissions. A dying breed admittedly, but my brother-in-law remains active.

[Brew Man]

Hmm, it would be interesting to know how far and how strong radio emissions would extend from a modern loco motor, though admittedly there are still plenty of much older locos with beefier motors hurtling hurriedly round modern day track.