23 Sep 2011

Bachmann suburbans - part 7: Programming the TCS FL2

This little project keeps throwing up problems that seem to cost a lot of time - firstly the locolamps not working, then the pull up circuitry to get the FL2 to work with the FF2 and now I hope a final problem - programming the FL2.

I don't want to do anything very sophisticated on the FL2 side but I did find that I couldn't use button 2 on the throttle to control the tail light (this is because on the digitrax throttle button 2 is not latching). Now there are various ways of programming DCC decoders - normally I only program on the programming track but on this occasion I used "ops mode programming" - in this the device does not need to be connected directly to the programming track instead the programming instructions are "sent" to its address and it can be on the main track.

Since my circuit was on my desk on the other side of the room from the programming track where i only had a connection to the main DCC rail supply I used ops mode programming. This worked fine to change the button for controlling the purple wire / locolamp - by loading CV 36 with value 16 I was able to change it to use button 3.

I was then stupid and went through the process of changing the FL2 to 4 digit DCC addressing, this is a multistage process and you first have to set CV 29 to 38 then load CVs 17 and 18 with some calculated values. The problem is that once you set CV 29 to 38 the "ops mode programming" ceases to work - as presumably the decoder is now at 4 digit address 0000 - only that isn't really a legal address and not one that you can use the digitrax to send stuff to. The decoder is now lost in (address) space. So now the only way of controlling the decoder until you have sorted this out is to put it on the programming track.

The problem I then found (and reading various internet boards I am not alone) is that I was unable to get the FL2 to respond on the programming track - argh!

I contacted TCS support who suggest a few things - but eventually I found the following - programming on the programming track only works if I disconnect the FL2 from the FF2s - The circuit I used was maybe over the top - but I put a resistor and LED on one funciont wire - the LED will then flash when programming happens giving you some visual feedback - I also connected a 47ohm resistor across one of the function wires and the blue return wire on the FL2. There was conflicting info from TCS if this was necessary or not - the instructions said yes but the support people said no.

Because the FL2 comes with a separate harness at least you can make up a harness for programming on the programming track to set four digit addresses and then do all other programming in "ops mode" on the main.

Circuit I used for programming the FL2 on the programming track using a digitrax DCC system...

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22 Sep 2011

Bachmann suburbans - part 6: Circuit Diagram

So I have ended up using two FlickerFree units to control the two sets of lights - one FF2 to control the carriage light and one to control the rear light. The rear light you could just control from the FL2 and live with the flickering but I have decided not to.

Here is the circuit that I ended up with after much messing about...note that there are actually twelve tiny leds for the carriage lights - only four are shown..also note that the two resistor values are not to be confused 47Kohm is required for the locolamp -less than 10K would probably damage it- wheras 47ohm is required to get the 12 carriage lights to have the sort of brightness one might want (less than you initially think).

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20 Sep 2011

Bachmann suburbans - part 5: Bogie conversion

The first job to do on the bogie was to change it to a Kadee coupling

I am using the technique I found by a contributor to Model Rail Forum here Which involves unscrewing the coupling bracket and then cut off the vertical section that holds the old tension lock then drill a hole as far forward as you dare in the now forward most horizontal section of what remains. Use that hole to bolt on a Kadee 46 and then remount the whole unit upside down - voila its magically at the correct height.

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After fitting the kadee then on the rearmost bogie of the brake van (i.e. the one underneath the guards/parcel area where we are going to locate the electronics) then I fitted the brelec pickups - these are expensive and fiddly - especially getting the little 'rivet' to go through the hole you have to drill without dropping everything and having to crawl around on the floor to find all the pieces (repeat until you get fed up). I will reserve judgement on whether cost/effort was worth it until i see how they work.

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10 Sep 2011

Bachmann suburbans - part 4 Fixing Leds

Looking back on some earlier advice from Richard of DCC concepts on use of Flicker Free with FL2 I realised that what was missing (though you won't find instructions to tell you this anywhere).

You need to connect the blue 'return' wire on the FL2 to the green wire of the FF2 via a pull up resistor (10K seems to be fine).

Doing this and voila I now have DCC control over the lights via the TCS FL2 decoder and the FlickerFree unit.

[I will put up a circuit diagram when I have finished tweaking later on].

So I went ahead and fitted the strips of LEDs into the open carriage.

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My next job is to fit the DCC concepts LocoLamp onto the back of the brake coach. It is amazingly small - it is marked here with a red arrow.

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It isn't brilliantly positioned and I have just used regular plastic kit glue to fix it.

Getting to the point where I was confident enough to fix the locolamp was a long story - I had a whole pack of them (thirty quids worth) that just didn't seem to want to work for me - they are easy to blow up but even so! That pack has been sitting in my cupboard for several years so in frustration I purahcsed a new pack and these seem to work fine.

One trick to learn is how to remove the enamel insulation of the tiny leads that supply the locolamp. There are several techniques - you can burn it off - but this is a bit uncontrolled, or you can gently wipe with an emery cloth being careful to put no strain on the connection - neither are great. and stripping the insulation remains a bit of an art form.

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6 Sep 2011

Bachmann suburbans - part 3: Microconnectors

I have lashed up a simple set of connections between the FL2 decoder and the DCC concepts FlickerFree2 device and the lighting strip - initially this does not seem to work.

Pressing button 1 on the controller should toggle the lights on and off - but it doesn't.

So while I scratch my head about that I have drilled some holes in the ends of the carriages for the Miniatronics microconnectors.

They are only an interference / friction fit at the moment - and O am hoping they can stay that way.

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5 Sep 2011

Upgrading the Bachmann Suburbans - Part 2: Bill of Material

By connecting the carriages I can control their lighting as a single unit which is nice and also I lower the cost of the fit out by using only one decoder and one FlickerFree unit.

The Flicker free units were devised by Richard of DCC concepts for DC originally - and they contain a large capacitor to drive the leds even when pickups aren't working - e.g. when train is stationary. Of course on DCC when the train is stationary the rails are still live - but the FF2 still has a purpose - firstly it allows more LEDs to be driven than a typical lighting decoder - and in the packs you also get the really hand lighting strip PCBs and some nice microdot LEDS that are ideal. The FlickerFree2 pack come slike this...

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and once opened you can see lighting strips FF2 units leds and a handy pack of 1K resistors.

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So now I have my complete bill of material - and it looks something like this -

Seated passengers - From ebay seller everest model on ebay £8.99 for 60pcs
Kadee couplings - in stock but probably around £5 for a pack
Pickups - Brelec - bought from DCC Supplies - £4.50
FlickerFree2 from DCC concepts bought from Digitrains - £58.32 for pack of 6
Microconnectors - Miniatronics bought from Digitrains - £8.32 for pack of 2 pairs
DCC Decoder - TCS FL2 lighting only decoder bought from Digitrains - £14.82

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I did consider using electrical connector couplings but as their are no NEM coupling sockets this would have been hard. I am also trying the brelec pickups to see if they are easier than just a bit of bent pickup wire. The axles on the suburbans are not conductive at all and so

So overall if you take one sixth of the FF2 pack and passengers set and a half of the connector pack then you get a total cost for the pair of carriages of around ( (8.99 + 58.32) / 6 ) + ( 8.32 / 2) + 14.82 + 5 + 4.50 = £39.70

Which will almost double the cost of the two carriages which are currently retailing for around £19 each online.

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4 Sep 2011

Upgrading the Bachmann Suburbans

I like the Bachmann suburban coaches they fit in well with the time and place of where I am proposing to model (Banbury 1962) but as models they are rather dated in a number of areas. For example they do not have NEM couplings.

Here is a slightly out of focus picture of one -

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I have one pair of these coaches and they will always run together. So I would like to do the following -

Add some passengers
Add lighting (both interior and rear oil lamp)
Change the couplings to Kadee

To add the lighting then there are choices to be made - do I want to have DCC control of the lights?, how am I going to make the pickups work? do I want each coach to be independently controlled and fed with power or shall I have them as a pair?

In fact in this case it is an easy decision - as these coaches will always run as a pair - I think the thing to do is put a single DCC decoder in the brake compartment and then join the coaches electrically by some means - this means putting the pickups on the same coach as the decoder only.

I will cover the choices of components in more detail in the next post - in the meantime here is how to take the coaches apart...

The first task is to remove the bogies - simples - undo the obvious centre screw in each. Removing the body is a little harder - it is held by six clips on the body that need to be prised away from the cut outs in the side of the base plastic.

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Once the body is off then you find that the same six clips that held the body to the base also hold the interior mouding in place - the interior moulding needs to be prised over the clips

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Once inside my first job was to glue in some lucky passengers using regular airfix type glue - in this case Revell Contacta.

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OK those are the easy bits done, next I have to work on the harder stuff of electronics and connections before doing the very tricky looking hack to get Kadee couplers to work with the stock.

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1 Sep 2011

DCC conversion on a Bachmann 4MT 4-6-0

I don't write up most of the DCC conversions - only those ones are slightly tricky - as much for my own aide meoir as anything else.

I have recently added a decoder to a Bachmann 4MT 4-6-0 - getting the body off is not too bad - as long as you identify the right screws - to get to the front one you have to look under the front bogie - an access hole is provided in the bogie to get at it. The rear one requires the brake work plastic to be moved to one side - as shown below.

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Once the body is off then I found my favourite TCS DP2X-UK wouldn't fit in the space and went for a decoder with a harness - shown here is the Bachmann three function decoder. I have had problems with these before and the only reason I used it here was that it was the best fit into the space in the boiler...

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In fact I got very erratic running (loco suddenly bolting and suddenly locking still) so I gave that up as a bad job and went for a LENZ silver instead which was harder to fit in the boiler space but works perfectly.

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