Converting Bachmann A4 (Mallard) 31-952 to DCC.

Post all your DCC only problems, solutions and discoverys here.
AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sun May 12, 2013 3:00 pm

Hello!

I've just found a bargain A4 at a show, I've always wanted a Mallard, found this one, had to have it.

I knew the loco was not DCC Ready before I bought it, but, I looked on a certain model website that states that it is compatible, but no socket is fitted...so, knowing a mate who converts, I purchased it. I didn't see much risk, especially when you can convert models years/decades old to DCC. Anyway, I've not been able to get hold of y mate today so I spent some time searching for a topic about it on the forum and I'm not sure if it is as straightforward as I first thought...mainly because I haven't found anything yet...or perhaps that means it is straightforward, as nobody ha to ask about it.

Has anyone converted this loco? Is it possible and is it straightforward?

Thanks!

Bigmet
Posts: 8198
Joined: Tue Aug 14, 2007 2:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby Bigmet » Sun May 12, 2013 4:42 pm

Must be a split chassis model. This is one of the easier split chassis to convert, because it is a good roomy loco. There is space for a decoder both ends, flat against the back of the body, or in the streamlined nose where there is a void. This general topic has been answered here so do a search on this site, or alternatively google 'bachmann split chassis DCC conversions' and you should turn up several how to guides, some with pictures. (I would normally pull up an example but am currently in the back of beyond on a very slow link.) The conversion priciples are the same on all the Bach split chassis steamers, it is just the detail of where the screws that hold it together are located that varies. There is a downloadable diagram on Bachmann UK's site if you don't have the service diagram originally supplied with the A4.

Test the model for good running on DC, and be aware that they do need a little more maintenance to keep them running sweetly. If you decide to go ahead with it, while you have the chassis apart, use some fine flexible wire (spare wire from decoders can be good) to connect the leading bogie for pick up. The bogie frame is screw assembled. Follow the scheme used to connect the trailing truck. The chassis connections for the trailing truck are ideal terminals for wiring decoder red and black to.

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sun May 12, 2013 4:49 pm

Apparently this one is a solid chassis...according to Bachmann's website...is that a big issue?

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sun May 12, 2013 5:09 pm

Saying that, the service sheet does show a chassis that splits in 2...

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sun May 12, 2013 5:38 pm

Right, I've just unscrewed the body and can confirm it is definitely a split chassis...which I'm sure everyone else already knew...silly Bachmann!

So it is do-able? Excellent news. I have had a look at various how to guides etc. but it's not something I feel comfortable doing myself as I'm not knowledgeable enough about the motor and wheel gearing to rectify any mistake I make. I'm pretty sure my mate who does weathering/loco detailing/DCC fitting can do it (he does excellent work if you ever need a weathering job done)..if not, can anyone recommend a service/shop who would be able to carry out the work for me?

Thanks for getting back to me!

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sun May 12, 2013 7:49 pm

Bigmet wrote:If you decide to go ahead with it, while you have the chassis apart, use some fine flexible wire (spare wire from decoders can be good) to connect the leading bogie for pick up. The bogie frame is screw assembled. Follow the scheme used to connect the trailing truck. The chassis connections for the trailing truck are ideal terminals for wiring decoder red and black to.


I've had a look at something on the RMWeb archive, it simplifies the conversion quite well and it doesn't seem as hard as I first thought...I'm not sure about this extra pickup business mind...how does that work? Do I need to put copper pickups anywhere? Do I just run the wires (now connected to the leading bogie-I'm guessing the 4 wheels that "hang loose") along the side of the chassis (insulated of course) and the connect to the same terminals as I'd be connecting the red and black decoder wires too? (Obviously keeping right side and left side the same)...how do you connect the wires to the wheels for pickup and are the axles insulated already?

The one thing that confuses me a little bit it where the decoder wires go when you reassemble the chassis...they'll be connected (and insulated) to the motor terminals, do you just have them running between the 2 halves of the chassis and out the back? I know decoder wires are very fine so I can't imagine they'd get squashed when you screw the chassis back together. Am I correct?

It seems as if all you need to do insulate the newly soldered terminals from the chassis, then insulate the rear of the chassis from the decoder...does that sound right?

So, to sum up, that's 3 questions:

1. How do you connect the wheels for pickup? I would trail the wire along the chassis and solder them to the terminals at the back.

2. Do the wires that now extend from the terminals on the motor (to the decoder) just sit between the 2 halves of the chassis when screwed back together?

3. Decoder wires to terminals, insulate, replace, solder other decoder wires to rear terminals, insulate read of chassis from decoder...is it that simple? (care being taken of course...)

Thanks for help

User avatar
siquelme
Posts: 869
Joined: Mon Jan 03, 2011 1:35 pm
Location: 71D - Portsmouth, UK

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby siquelme » Wed May 15, 2013 10:39 pm

Did you buy it in Derby by any chance ;)
Great Western Modeller for my sins
My Blog http://brookescastle.blogspot.com/

GWR_fan
Posts: 4750
Joined: Sun Apr 29, 2012 11:57 pm
Location: Antipodes

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby GWR_fan » Thu May 16, 2013 8:08 am

Try this link for the A4.

http://www.rmweb.co.uk/forum/viewtopic.php?f=49&t=16101 (this may be the RM archive you refer to)

Tim

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Sat May 18, 2013 9:45 pm

Yeah, that's the how to I've read...apparently, it's a lot harder than that article makes out so I'm not going to attempt it myself.

Oh and yes, from Derby :)

Mike Parkes
Posts: 766
Joined: Sat Sep 01, 2007 8:25 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby Mike Parkes » Sun May 19, 2013 11:34 am

Looks like a pretty standard dcc conversion of a split chassis loco, strip it right down and reassemble. If you do change your mind one thing thats is a useful precaution is not to connect the decoder wires directly to the motor, use another pair of wires, reassemble the whole thing and then check for any shorts with a multimeter. If there are none connect the decoder to the two wires from the motor using heatshrink to cover the connection, or if space exists use a small bit of copper clad stripboard to make the connections on.

Bigmet
Posts: 8198
Joined: Tue Aug 14, 2007 2:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby Bigmet » Sun May 19, 2013 11:38 am

Unless you have a friend prepared to do the work, expect to pay a fair amount for a DCC conversion; and realise there is a risk. This is both because it takes time, and there can be problems on the chassis which are only discovered once it has been dismantled to the extent necessary to isolate the motor, and these sometimes only show up once the re-assembled model is back with the owner and has run a little.

I do quite a lot of decoder fitting for friends on an amateur basis, and now refuse to touch Mainline or Bachmann split chassis. I have run through pretty much all the accumulated spares that I had to hand from worn out specimens of my own, and it was these that made it possible to work on the split chassis. When you are presented with a loco that runs well enough on DC but on opening up (as carefully as possible) every single one of the plugs that are used to hold the chassis halves together are broken and not re-usable, a couple of the axle insulating centres literally fall apart, the baseplate splits or cracks in flexing to disengage from the clip on points on the chassis block: without the spares you are stuck with making a lot of repairs and replacement parts, very tedious.

With conventional wiper pick up chassis now available suitable for pretty much every former split chassis item, my suggestion is that the model with the good replacement chassis is purchased as cheaply as possible, and that chassis used. Quick, simple, reliable; essentially trouble free.

AVFCAM
Posts: 53
Joined: Mon Feb 06, 2012 10:19 pm

Re: Converting Bachmann A4 (Mallard) 31-952 to DCC.

Postby AVFCAM » Tue May 21, 2013 11:05 pm

I've had a quote from a reputable shop, well, I've had 3 quotes all for about £30 including the decoder (£17 conversion).

My loco is brand new, never run, so I'm hoping there's no problems with the chassis. I've spoken to enough people now to think it shouldn't be a problem to get it done, but I am always glad of the advice of other modellers.


Return to “DCC Forum”

Who is online

Users browsing this forum: No registered users and 7 guests