Class 37 DCC Conversion stuttering at low speed

[RiverbankRailways]

Brand new to DCC control an in the process of converting my old locos from the 80s. I have added a Hornby R8249 4 function chip to a Lima class 37. I am using the Hornby Select controller. The issue is that the loco is shuddering / stuttering when starting off at low speed. It happens in both directions but is perticularly bad in 1 specific direction. It also happens when the loco is slowing to a stop. 

Have a look at this video to see what I mean, especially half way through when it travels to the left: 

Here's what I have tried when troubleshooting:

1. The track is clean and perfect

2. I have tried a range of acceleration settings

3. I disabled DC mode on the controller

4. I reset the controller to factory settings

5. I checked all the soldering and connections

6. I have removed the capacitor between the two motor connections

7. Before the conversion, the loco was cleaned and serviced and running perfectly at low speed on DC.

I am aware that there are other decoders available which give more access to the cv settings in the chip for sorting these types of issues. As I said I am just getting back into this and starting off with Hornby, but plan to expand. I also am aware that the loco is old and may cause problems like this.

My plan is to add more chips to my other locos and see if the same issue happens or if it is particular to this loco.

If anyone could shed light on this issue or suggest some more troubleshooting tips, I'd really appreciate it!!

 

Thanks in advance :)

RR

[Fishmanoz]

I can understand why you have few replies RbR - you've already covered just about everything. 

One question - did you hard wire the 8249 or install a socket.  I have the same advice either way, just easier if you have a socket.  For a start, I would suspect this is a one-off, not common to all your older locos as they should work on DCC if they work well on DC, as I'm sure you've already gathered given your level of knowledge.

 

So my advice - if you have another 8249, swap that in to see if it is a faulty decoder.  If no improvement, try another brand.  User ColinB on here seems to have had a lot of success with Zimo with his older locos, if I remember correctly. 

[2e0dtoeric]

Have you removed any/all capacitors in the TRACK? If you have used power-connecting tracks, they have caps built in. If you've hard-wired and soldered, then that doesn't apply, of course.

Were you using an ultra-sonic track cleaning device before? If you have not removed it, that can kill your decoders.

[RiverbankRailways]

I can understand why you have few replies RbR - you've already covered just about everything. 

One question - did you hard wire the 8249 or install a socket.  I have the same advice either way, just easier if you have a socket.  For a start, I would suspect this is a one-off, not common to all your older locos as they should work on DCC if they work well on DC, as I'm sure you've already gathered given your level of knowledge.

 

So my advice - if you have another 8249, swap that in to see if it is a faulty decoder.  If no improvement, try another brand.  User ColinB on here seems to have had a lot of success with Zimo with his older locos, if I remember correctly. 

Brilliant, thanks Fishmanoz! I did cut off the plug and soldered in the wires for the 8249 and I have a couple of extra ones so will try another logo and post here with the result - hopefully it's a one off as you say. 

 

I had also planned to buy a couple of Lezn decoders and experiement with them as well and will throw in a few Zimos and see how they go - thanks for the tips :)

[RiverbankRailways]

Have you removed any/all capacitors in the TRACK? If you have used power-connecting tracks, they have caps built in. If you've hard-wired and soldered, then that doesn't apply, of course.

Were you using an ultra-sonic track cleaning device before? If you have not removed it, that can kill your decoders.

Thanks Ericm0hff :) The wires are soldered to the track, no connectors and I'm not using a device to clean the track, just some goo gone and cotton buds for the moment - don't have the full layout set up yet, just a test length of track - thanks for the suggestions though!

[The son of Triangman]

 

Was the loco a good runner before conversion?  

 

[Chrissaf]

RiverBank

Could I please draw your attention to the TIP for newbies below:

 

TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

 

See also – further TIPs on how to get the best user experience from this forum. TIPs include 'How to post images' and 'How to make links clickable'.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

 

[2e0dtoeric]

@Margate - 7. Before the conversion, the loco was cleaned and serviced and running perfectly at low speed on DC.

[RiverbankRailways]

"Could I please draw your attention to the TIP for newbies below:"

 

Thanks Chris :)

[RiverbankRailways]

Just an update on this issue for any future readers, the class 37 above was a Lima model so to rule out whether this issue was due to a single faulty decoder or the fact that a Lima model was used with a Hornby decoder, I tried adding another Hornby 8249 decoder to a slightly newer Hornby class 47 I have.

 

Unfortunately the exact same thing happened, the loco ran pretty ok in one direction with an acceleration setting of 9 (which gave the least shuddering), however in the opposite direction the engine stuttered again at low speed (even worse than the class 37).

 

I also tried reversing the loco direction setting on the controller to check if it was a mechanical issue and the loco then ran fine in the direction in which it was previously shuddering, but started shuddering in the direction it had been running fine in!! This indicate a possible issue with the Hornby Select controller running in the forward direction...

 

So, on advice above I have ordered 2 each of Bachmann, Zimo and Lenz decoders to see if they function any better and have also bought a Lenz LH100 contoller set to see if any combination of decoder and controller will resolve the issue. I had planned to buy these anyway as I only got the Hornby ones in a train set so as to explore DCC while getting back into the hobby, so no harm done, just my plan was accelerated a little :)

 

When I test these, I'll update this post with the results for any future readers that may have a similar issue :)

 

Stay tuned...

[ColinB]

I found choice of decoder was really important on old locos. New locos with decent pickups and efficient motors you can use virtually anything. On my old Limas I added an extra pickup to the dummy bogie and used Zimo decoders that seemed to make them work a lot better. I have no association with Zimo, but I have noticed they seem to work much better that a lot of the others with a less than perfect DCC signal.

[Flashbang]

My 'rule of thumb' is where any older type of motor is used, and more importantly it runs 100% on DC power, is to always fit a "Quality" make of decoder. e.g. Lenz Standard or Silver or Zimo are excellent makes and offer far improved motor control including Bemf regulation which improves motor control.

Basically the better the decoder the better the motor performance

[RiverbankRailways]

Thanks for all the advice and replies on this topic everyone :) Success!!

 

I received the Lenz controller and tried using that with the hornby decoders, but that didn't solve the issue. 

 

However after fitting a Zimo MH600 decoder, another old loco (a Lima class 33, approx 30-35 years old) ran perfectly, so the solution (for anyone else reading this and having a similar issue) was to use a better decoder as many of you suggested :)I will still test out the Bachman and Lenz decoders on my other locos (and replace the Hornby decoders I installed) to see how they get on and will post the resuts here for anyone else reading thie thread in the future.

 

Thanks again community :)

[RiverbankRailways]

As promised, here's a video of the same loco running with a Zimo MX600R wired decoder and two other locos running with Lenz and Bachman decoders

 

Zimo: 

Lenz: 

Bachman: 

 

Here's my quick Pros and Cons assessment of Zimo vs Lenz vs Bachman after doing some testing

 

Zimo MX600R Wired DCC Decoder

Pros

- Protective sheath

- Extra function wire (9 wires in total)

- Perfect running out of box

Cons

- Price: €22.24

 

Lenz 10231-02 Digital Standard +V2 Lok 8 pin

Pros

- Price: €17.72

- Perfect running out of box

Cons

- No protective sheath on chip

- No extra function wire (8 wires in total)

 

Bachman 36-566 0.9 Amp 4 function 8 pin

Pros

- Price: €14.93

- Protective sheath

- Extra function wire (9 wires in total)

 Cons

- Required changing of CV values to get perfect running

 ----- ----- ----- ----- ----- ----- ----- 

After comparing the decoders, I think I'll be going with Zimo - although a little more expensive, but they worked perfectly without adjustment, have a protective sheath, a flat bottom for easy sticking and just gave silky smooth running :)

Hope this helps someone else!

[ColinB]

This is probably not the thing to say on this site but my experience is only use Hornby DCC decoders (TTS decoders included) on modern Hornby Locos (even with 0-4-0 locos sometimes there are issues) and modern Bachmann ones. Most of the older locos draw too much current. Actually the Zimo is cheaper or about the same RRP as a Hornby one, it is just most retailers sell them at a discount. The Train O Matic ones seem to work ok with older locos as well.

[RiverbankRailways]

Thanks for that info ColinB :) 

[Flashbang]

This is probably not the thing to say on this site but my experience is only use Hornby DCC decoders (TTS decoders included) on modern Hornby Locos (even with 0-4-0 locos sometimes there are issues) and modern Bachmann ones. Most of the older locos draw too much current. Actually the Zimo is cheaper or about the same RRP as a Hornby one, it is just most retailers sell them at a discount. The Train O Matic ones seem to work ok with older locos as well.

Are you serious in stating "only use Hornby decoders in modern Hornby locos"??

The basic decoder produced is far from good. The TTS is frequently shown as failing for unknown reasons. Other makes that are available offer far, far better loco motor control than the basic H one does. The only exception is the Sapphire which is a reasonably good allrounder.

Yet in your last paragraph you intimate that Zimo or Train O matic are better. Contradiction surely?  

[Rog RJ]

Colin is saying don't use them in older locos (that take a high current) but they should be ok in new, low current, models.