Dapol 45xx with chip and on analogue

[norman]

I've just bought a Dapol 45xx and its a really good model at a very reasonable price but behaves rather strangely on analogue DC.
Needless to say on DCC it works very well and without the decoder it works normally on analogue DC.
But on DC with a decoder fitted it works perfectly in reverse but does not move forward. I have tried it both ways on the track. It has been suggested that this is a result of the coreless motor. If I try to run it on address zero using my Lenz DCC with no decoder fitted it does not move. Very strange.
I think that the suggestion that its because of the coreless motor is just a possibility but can anyone explain why this happens?

[Nigelcliffe]

From the description, it's a problem with the decoder, or the nature of the "DC" being supplied to the decoder.  

 

What happens if you run it on absolutely pure DC - for example a 9volt PP3 battery connected to the rails ?  Does it then go backwards and forwards ?  

 

Can't see the relevance of the coreless motor to the behaviour reported.  

 

 

 

 

[D9020 Nimbus]

Is this an O gauge or an N gauge model?

[WIMorrison]

I would avoid running anything on Address 0, especially a coreless motor

[norman]

I have now fitted a Dapol 21 pin decoder and the analogue DC works forward and reverse. 

I then removed the Dapol decoder and replaced it with a Zimo MS440C sound decoder courtesy of Youchoos (just arrived - which only took 10 days to travel less than 50 miles with Royal Mail) and this works great forward and reverse on DC too.

So clearly a problem with the Zimo decoder first fitted.

As to running on address 0 on Lenz, I have used it for several years now and never had a problem and I think its just part of the urban myth that it should be avoided.

 

[Izzy]

I don’t believe Dapol fit coreless motors in any of their locos in either N or O. They are either sealed flat cans or in N sometimes the ‘super creep’ open frame type.

[WIMorrison]

34 minutes ago, norman said:

...

As to running on address 0 on Lenz, I have used it for several years now and never had a problem and I think its just part of the urban myth that it should be avoided.

 

Most definitely not an urban myth, as I can personally testify. In my early days of DCC 20+ years ago I had a Lenz setup and used the Address 0 'trick' on locos but suffered from two motors burning out. This could only be caused by Address 0 as I did have any DC to run the layout with and these locos were used from new exclusively on Address 0 using the Lenz controller. 

 

It is interesting that Address 0 isn't used by anyone else, and I don't think that Lenz advertise its use now.

[norman]

You can use address zero on Digitrax too.

 

 

[WIMorrison]

Strange that only the two original manufactures implemented Address 0, and that the manufacturers that came along later with more modern designs haven't implemented Address 0 - surely that also says something 😉 

[Hamburger]

3 hours ago, norman said:

I think its just part of the urban myth that it should be avoided.

 

DCC address 0: compare it to a walking person:

 

1. Pure DC (e.g. battery) is like riding on a treadmill (like those found in some airports).
2. DC rectified from AC is like normal walking.
3. AC on a DC motor is like stepping forward and then stepping back.
4. AC on an AC motor is like stepping forward, turning 180°, stepping backward, turning again, etc.
5. DCC directly on a DC motor is like doing a very small or small hop forward, followed by a very small or small hop backward.
6. DCC on address 0 is like doing a very, very big hop forward, followed by a very small or small hop backward.

 

One can imagine that when a human moves like 6., it will take a lot of energy and only strong people will be able to keep it up longer. Less robust or very old people will work up a sweat very quickly and may even injure themselves.
Accordingly, a motor will heat up considerably and it depends on the type of motor how long it can withstand this.
At 3 . or 5 . even only heat is generated, a movement does not take place or hardly takes place.

[NIK]

Hi,

 

The symptoms you had on DC with the original fitted decoder could have been due to problems with the diodes or the surrounding PCB tracks on the decoder that rectify the supply from the track pickups and feed the decoder with DC power. If one half of the full wave rectifier stops working* then the rest of the DCC decoder won't get power when the DC controller is in one direction.

 

* on DCC the decoder will only draw current from the rectifier half the time but if the motor has low enough current draw a drop in top speed may not happen or be noticed (the capacitor supplied by the rectifier should keep the rest of the decoder going if the total current draw is low enough).

 

With the present shortage of DCC decoders due to the worldwide integrated shortage it's probably worth hanging onto the decoder.

 

Regards.

Edited September 16, 2022 by NIK