Choosing a decoder (small, hard wired, split chassis)

[Tomathee]

Evening, I've been given a few old locos, most don't fit with my layout and ideas so are destined for display but one fits perfectly with an idea for a potential expansion so I want to utilise it, so the relative knows it's gone to a good home and to save me a bit in buying one. There are a few issues, as per clues in the title, it's an Ivatt tank (Bachmann, 00) from the times before DCC and with a split chassis. I've found a video guide for doing the install on this specific loco but I can't find the decoder they mentioned, so looking for guidance on that, and whether I should stop at decoder or add a stay alive and sound.

So far I've either bought DCC already fitted or with the other more modern locos I have, gone by the socket size when buying decoders, or more videos around with suggestions as they're from the time of youtube etc. I had a look on a few sites and couldn't be sure on what I needed so any specific recommendations would be useful. I didn't particularly want to go down a research rabbit hole this time as it'll most likely be the only time I do something like this. For example from DCC concepts I think a 'Zen Blue+ Decoder: NEM651 6-Pin Direct – 2 Function' is an option (don't think I need the harness version). I was looking at the space inside and thinking about a stay alive too, but that's also something I haven't done before so not sure what I need to consider on the decoder side, on DCC concepts website it sounds like most have a 3 pin connector to go with their stay alives, but I'm not sure how it works with other websites I've been looking at. As part of researching the installation I came across a sound fitted example however using a newer version of the model. It used the bottom of the cab floor as space for the speaker so I'm thinking whether I should go all in at the deep end but again I'm even further from knowing what I need to complete that in terms of speaker and presumably a more advanced (and bigger?) decoder.

 

Any pointers appreciated.

[brossard]

I've tried to add decoders to split chassis locos with mixed results usually dire, maybe my workmanship, although I've done a lot of regular locos successfully.

 

Before you do anything, check the plastic insulating axles, these are prone to cracking whereupon you lose quartering.  There are 3D printed replacements around IIRC.  I recall that the motion is difficult to disassemble.

 

John

[Combe Martin]

 

I've got a split chassis Bachmann Ivatt tank loco, had it since pre 2010, and I fitted it with a Digitrax DN135 which is a small hardwire decoder (from memory about 1 cm square), I also fitted this decoder to a Bachmann 46xx pannier tank and a Bachmann Jinty tank both of which were non DCC ready and at the time I wasnt sure whether I'd get my usual hardwire decoder (ZTC255 which isnt big like a Lenz Standard) in them.  In the Ivatt I put the decoder in the bunker (I cut out the moulded coal and replaced that with a lid covered in real coal, it was easier when refitting the body to the chassis.  I'm in the process of building a new layout in a new house and I've just dug it out (it hasnt run since pre 2016) but I fired it up and it ran straight away without any problem. 

 

I've never found the need to use 'stayalive', I've always had the impression that its more needed if you fit sound which I don't do because I'm Steam only (Somerset & Dorset in the 60's). 

 

I can give you the CV values I used if it'll help.

Edited April 26 by Combe Martin

[rogerzilla]

Wickness Models used a Lenz Silver Mini in my Farish 03, which is split chassis and very small!

[Izzy]

The question is not whether the chassis is live to one side, as with many locos such as the Farish 03/04/08 etc. but whether the motor is isolated from it, which they are I.e. no brush connection directly to the chassis or the motor body itself being ‘live’. This is where the issues can lay if they are.

 

Bob

[34theletterbetweenB&D]

This was one of Bachmann's products from their initial probe into the UK OO market. The mechanism is a low cost construction with numerous weaknesses, well documented by a good many postings here and elsewhere. That said, the lighter locos - of which this is one - do tend to greater longevity.

 

I'd suggest not going overboard on it, just a decoder to make it a runner, with the proviso that first you open it up to make the modifications essential to isolate the the motor terminals completely from both chassis halves. It is not necessary to take the outside rods off the coupled wheelsets, just take the glued on cylinders off the chassis block stubs and then drop the complete assembly out once the keeper plate has been removed. What you will find inside is hard to predict, it may all be in good condition, or alternatively the many essential plastic components  that provide the isolating function between the chassis halves may be failing. And test and test again on reassembly to be certain that both motor conections are fully isolated from the chassis halves

 

I successfuly converted a good number of the LNE group models to DCC about 20 years ago, and they lasted four to six years in intensive operation, with much swapping of any parts with life left in them until I had worn through the plating on all the wheelsets; one exception, a particularly good early A4 mechanism with much heavier plating that still runs, long ago fitted with a Hornby A3 body, that mechanism and body combo is now coming up 30 years old.

 

The motors in all these were good, they appear 'unburstable', and I also salvaged bodies, bogie and trucks, etc. for repurposing, so not a total loss.

[Tomathee]

On 27/04/2024 at 16:42, 34theletterbetweenB&D said:

This was one of Bachmann's products from their initial probe into the UK OO market. The mechanism is a low cost construction with numerous weaknesses, well documented by a good many postings here and elsewhere. That said, the lighter locos - of which this is one - do tend to greater longevity.

 

I'd suggest not going overboard on it, just a decoder to make it a runner, with the proviso that first you open it up to make the modifications essential to isolate the the motor terminals completely from both chassis halves. It is not necessary to take the outside rods off the coupled wheelsets, just take the glued on cylinders off the chassis block stubs and then drop the complete assembly out once the keeper plate has been removed. What you will find inside is hard to predict, it may all be in good condition, or alternatively the many essential plastic components  that provide the isolating function between the chassis halves may be failing. And test and test again on reassembly to be certain that both motor conections are fully isolated from the chassis halves

 

I successfuly converted a good number of the LNE group models to DCC about 20 years ago, and they lasted four to six years in intensive operation, with much swapping of any parts with life left in them until I had worn through the plating on all the wheelsets; one exception, a particularly good early A4 mechanism with much heavier plating that still runs, long ago fitted with a Hornby A3 body, that mechanism and body combo is now coming up 30 years old.

 

The motors in all these were good, they appear 'unburstable', and I also salvaged bodies, bogie and trucks, etc. for repurposing, so not a total loss.

 

Thanks for this and all the other responses. I've ordered a decoder and will report back on the outcome next week hopefully.

[WIMorrison]

Some excellent decoders at very affordable prices from Tramfabreik. You will get what you want for ⅔ the price of the one that you quote.

 

Decoders (tramfabriek.co.uk)

 

I have used these for a while now, absolutely no complaints about them. They are widely used in Europe, just not known in the UK.

[Tomathee]

Hello guys, bit late but I wanted to round this off for any future explorers that unearth the thread. 

Following the cautionary words above I was caught in two minds over proceeding to DIY or find someone to do it for me, so reached out to a few places either for recommendations on decoders from their range or enquiries on the possibility of fitting one. Many steer clear of offering a fitting service for split chassis and a couple gave me a quote, however honourable mention to Digitrains for suggesting a decoder and stay alive (along with wariness on the likelihood of success, understandable and in line with others, would rather that than promise that which cannot be done). I also added some black tack and suitably sized insulating tube, to help with sticking everything down and for the crucial part of insulating what needs insulating. Further points for delivering within 36 hours of ordering.

On with the fitting, having a youtube guide for the specific loco helped a great deal, and in general it went fine with a couple of small obstacles. The wiring is fairly simple, between the manual and video it was a simple case of soldering the two decoder pickup wires (Lais 8 pin decoder) to the tabs that the pickup wires from the front pony truck join to. This was followed by soldering to the motor joints along with careful insulation. Fortunately all of the plastic parts seemed in good order. The decoder wires were long enough to reach into the cab/bunker area where I planned to secure it so I tested before adding the stay-alive, minor issue in not picking up the loco but realised this was due to not assigning an address. Stay alive also had plenty of wire length and was a simple two wires to the decoder. There is a shelf in the bunker which includes the screw holes to join chassis and body. It is a tight fit but I wanted to keep the screw holes so I removed the middle section with a dremel to give me a bit more space for placing things, further testing. Closing the body up was a bit of a challenge and where the wire/insulation is on one of the motor connections meant I had to leave out the cab detail part, similar to the video guide. I think with more forethought and a bit more risk in using a shorter piece of insulation it could be accommodated but I didn't want to start messing with the work I'd done. I think I could do a better job of hiding the stay alive, which is in the cab area when it could be further back under the coal piece, the decoder fits nicely along the floor.

In conclusion, it's been successful, to the point that with the stay alive it performs better than my newer J50, which says more about my track I suppose. Even on the lowest speed setting it works well and was a worthwhile exercise in my opinion. As mentioned this was a free gift and whilst I had it apart I cleaned off some of the paint that had been added to the wheels and gear, the next thing I need to do with the loco is add a couple of missing parts (steps, couplers) and then look at weathering, particularly the lower parts. Few photos below