DRS Class 20 juddering issues

[DevilsAdvocate]

Hi folks,

 

This is my 1st post on the site for a long while, so apologies if this has been covered previously.

I have recently purchased the two Bachmann DRS Class 20's, together with 2 x Bachmann 36-570 Plux 22 decoders.

The loco's are superb, and have been well worth the wait ( and some wait it's been as well ! )

 

However, one of them ( 20312 ) judders at slow / medium speed.

I have run this loco for about 10 days now, thinking it may need some running in, however it's quite evident the problem isn't going to go away.

 

I suppose the easy option is to give it back to the supplier for repair / exchange, but i'm hoping this is an easy fix without having to do that

I believe this 1st batch of these loco's has sold out, so getting a replacement may not be an option

I'm not great with changing CV's and stuff like that, and i'm only just getting used to a new controller i've purchased ( NCE Powercab ), so i'm a bit wary of this

 

As a matter of interest, i intend when funds allow, to put sound into these.

If this issue is Plux 22 related, the problem should go away i assume ?

 

Either way, is this issue likely to be a loco related problem, or a Plux 22 issue do you think ?

 

Any ideas / resolutions would be most welcome.

 

Cheers

John

[Izzy]

According to Bachmann this is a Zimo made product so motor control should be fine - apparently the details for the MX618N18 apply ( the Zimo small decoder manual/PDF will give all this info), which leads one to think maybe there is a loco issue somewhere. But a basic cv8 to 8 reset might eliminate the chance the decoders got a bit messed up somewhere along the line.

[DevilsAdvocate]

I have in fact been in contact this morning to Rails of Sheffield where i got it from and they have been very good about it, stating they will exchange it for another............Except they haven't got any !

Which is what i thought they would say.

They have stated they will put me down for a new one once the next batch arrives, but i don't think that will be any time soon, or give me a refund or credit note, which again doesn't really help as i cant get another one for the same price anywhere else.

 

I wonder if sending it back to Bachmann would be the answer, let them repair / replace ?

 

John

[Wacol]

 

Have you swapped the decoders between the locos to see

if the problem moves with the decoder or stays with the loco?

 

 

 

[DevilsAdvocate]

Hi Wacol

 

Sorry, yes I should have stated that in the original thread, I changed them over and it’s definitely the loco

im a bit disappointed there, as I hoped it would be the decoder, however as stated it’s the loco.

 

john

[Crosland]

24 minutes ago, DevilsAdvocate said:

however as stated it’s the loco.

 

What's it like on DC?

 

You should really only chip a loco once it runs well on DC but a good decoder can compensate for a few shortcomings. My kids's train set Thomas and Percy (really cheap ones, "Thomas" was an 0-4-0) ran really well with a DIY decoder. You might be able to, for example, tweak the Back EMF settings, to get the loco to run better on DCC. The Zimo manuals are quite comprehensive so it could be worth a try.

 

Do try the reset first, just in case the decoder isn't as new as you think it is 

Edited April 12, 2021 by Crosland
More info

[DevilsAdvocate]

Cheers Andy for that. 

Running a loco on DC for a period of time isn’t an option for me as I’m all DCC,  and I’m sure the decoder is ok, as it works perfectly on its sister loco 20306

These are brand new Plux 22 decoders from Bachmann, a decoder that by all accounts is to replace the 21 pin 557 decoder, but I will run the loco on my programming track to see if it’s still the same

 

john

[Nigelcliffe]

 

If swapping decoders results in no change to the problem loco, and the "good" loco works well with either decoder, then the issue looks to be mechanical/electrical in the problem loco.  

 

So, start looking for those sort of issues.  Obvious ones are:  too much gunky grease on gears,   drive shafts not correctly coupled from loco to bogie gearing,  pickups not aligned correctly on wheels,  faulty gears.    Less likely, but possible, may be parts on the loco PCB.  

 

You could try a warranty return to Bachmann, because a sensible strategy they might take is to swap the mechanism for another one.  But, perhaps find out whether they will do that if/when fault is found, rather than just declaring "oh, here's a nice shiny green one instead".  

 

There's nothing "special" about Plux decoders compared to other types. The difference is the pin connection form.   Plux as a pin-arrangement is a better standard than the earlier types as its properly defined and supports commonly expected stuff such as sound, stay-alives, and a decent number of lighting outputs.  (Unlike the MTC-21 pin which comes in two subtly different (and thus subtly incompatible) forms, or the 8-pin which lacks connections for speakers, stay-alives, or a decent number of lights).  

 

 

 

- Nigel

[DevilsAdvocate]

Cheers Nige,

 

I am a little bit scuppered here with this loco

I, like a lot of fellow modellers have waited an eternity for Bachmann to release these loco’s. 
In hindsight, I should have returned the loco to Rails immediately, however I gave it the benefit of the doubt, and gave it a chance to bed in

now, it’s too,late, they’re sold everywhere, except for the sharks on E Bay charging an arm and a leg

Rails charged £140 for this loco, the cheapest I have seen it, and they have been very helpful today to their credit 

they can’t replace it, because they like everyone else has sold out.

 

I appreciate your suggestions regarding grease, pick ups, gears etc, and I will look at these, thanks for the advice, however, I don’t want to give Bachmann any reason to tell me it’s been tampered with, invalidating the warranty, and they will

Any dealings I’ve had with them in the past have been unsavoury.

 

The next option is to take it to someone who’ll mend it, but then there’s a costing

 

In the first instance, I was going to plump for the sound fitted ones, but not at £279 each. That’s ridiculous money

 

Anyway, I’m moaning now, Ha Ha !
 

I’m pretty sure this is an easy fix for someone in the know, I’m hoping Rails will look at it first before sending back to Bachmann, I’ve got no choices really being as they are sold out

 

John

[DevilsAdvocate]

Just to add,I’ve tried the loco on DC and it still judders, I hoped it hadn’t as then it would have been the decoder obviously 

 

Never mind, it’s as you were

 

 

John

 

[Nigelcliffe]

2 hours ago, DevilsAdvocate said:

Just to add,I’ve tried the loco on DC and it still judders, I hoped it hadn’t as then it would have been the decoder obviously 

 

 

Presumably you mean "tried on DC with a DC blanking plug".   Because if you tried on DC with the DCC decoder still in place, then its running using the decoder.   

 

That said, all the symptoms say "not the decoder".   

[steve66]

Many years ago I had a split joint cup,the one at the motor end that connects the motor to the gear tower via the drive shaft,as the motor rotates bogie one is driving as it should correctly but because bogie two joint cup is slipping it causes the jerky running.for me the only cure was to replace the motor complete with tight joint cups,the joint cups look like they are pressed on and split sometimes.

Hope this helps with your diagnosis,of course it could be a completely different fault on your loco,that was the problem was with mine.

Cheers 

Steve

[DevilsAdvocate]

Hi again folks

 

Yes Nige, the blanking plug was fitted for the DC trial

 

Thanks Steve for the info.

I've just been in contact with Rails where i purchased it from  They've been very helpful and sympathetic regarding the issue, but they, like everyone else have sold out.

I did suggest if they had any Harry Needle examples if they could swap the chassis onto the DRS example and then reject the HN one.

Unfortunately the chassis is different

 

The only alternative i've got apart from reclaiming a refund on it and buying one off the sharks on E Bay, which i won't do and i hope they never sell theirs either at such ridiculous asking prices,

is to return the loco back to the shop for Bachmann to repair..

As a matter of interest they did say that Bachmann have now discontinued the Class 20/3 so it's possible no more will be produced

Not sure about that one myself. Its sold out almost immediately and so surely another run would be beneficial

 

So it looks like a return to Bachmann for repair

Turn around time is approx' a month i'm being told

 

John

 

[DevilsAdvocate]

Hi folks,
 

Just an update, I have  been assured I am eligible for a full refund on this loco, and I have managed to source one at last from another model shop for just another £9 extra.

I’m happy with that, these two DRS examples are very difficult to source even just a few weeks after release

 

All’s well that ends well

 

Thanks to all who offered their advice in trying to rectify this issue, & happy modelling !

 

John