Bachmann Derby Lightweight - Interior Lights

[signalmanmike]

Has anyone out there had experience of switching the interior lights on a Derby Lightweight using a DCC function?  At the moment, the lights are on whenever power is applied to the track. I find this really annoying particularly when the model is parked (in a siding, for example).  The lights are horrendously bright too, although I have sorted this by applying yellow marker to the LEDs.

 

Any advice, comment or practical guidance would be greatly appreciated.

 

Mike

[Xerces Fobe2]

Having just got around to fitting the decoders to mine I am afraid that the interior lights are on all the time. What  a pain to get these lovely units apart and fit decoders, come on Bachmann how about a decoder design clever?

 

XF

[SRman]

I think this applies to all of the Bachmann DMUs: the interior lights are wired with the marker and tail lights. Switching on function 0 in DCC turns on everything and switching F0 off turns off everything. It would have been nice if Bachmann had separated the light functions as they did with the 4 CEP units, where F0 turned on the headcode lights and F1 turned on the interior lights.

[Xerces Fobe2]

I think this applies to all of the Bachmann DMUs: the interior lights are wired with the marker and tail lights. Switching on function 0 in DCC turns on everything and switching F0 off turns off everything. It would have been nice if Bachmann had separated the light functions as they did with the 4 CEP units, where F0 turned on the headcode lights and F1 turned on the interior lights.

I despair how can a manufacturer design a simple lighting circuit which should be a standard for all similar models and then not use it in later products!  When are Bachmann going to realise that their deoders do not easily fit into the space provided  in their units.- the Class 105 DTC springs to mind.

 

It has taken me up to 2 hours to fit decoders to  Bachmann DMU's and EMU's getting the bodies of without damaging them can be very time consuming and replacing even more difficult.  This hardly inspiring to prospective new entrants to our hobby! Hello Barwell are you listening?

 

XF

Edited May 4, 2013 by Xerces Fobe2

[AMJ]

Yet they went the full function route with the BP!  I bet there is a simple solution similar to the tweaks to tail lights on diesel locos.  Will have a look when I have a chance.

[mcrook64]

Hi everyone

What a nightmare putting decoders into Bachmann derby lightweight dmu got it done but lights in power carriage don't come on.do you have to set the 2 decoders to same address so that the directional

Lights are in sync?, any advice I would be grateful.

[leopardml2341]

...............Hello Barwell are you listening?

 

XF

 

You'll have to shout MUCH louder than that.....................

[Ray H]

I suspect that part of the reasons for the difficulties in accessing the inside of the units is because Bachmann have to produce something that is both modeller and child friendly at the same time. From memory I had more trouble putting the body back on than I did removing it.

 

The lights in the power car problem is probably because the contacts are not being made on the inside of the roof. I tweaked the ends of the vertical contacts very slightly and overcame the problem.

 

Yes, both decoders need the same address. I believe that the DLW trailer car doesn't need the direction setting reversing relative to the power car, unlike some of the other units that have been produced.

[34theletterbetweenB&D]

I think this applies to all of the Bachmann DMUs: the interior lights are wired with the marker and tail lights. Switching on function 0 in DCC turns on everything and switching F0 off turns off everything. It would have been nice if Bachmann had separated the light functions as they did with the 4 CEP units, where F0 turned on the headcode lights and F1 turned on the interior lights.

I despair how can a manufacturer design a simple lighting circuit which should be a standard for all similar models and then not use it in later products!  When are Bachmann going to realise that their deoders do not easily fit into the space provided  in their units.- the Class 105 DTC springs to mind...

I have formed the impression that Bachmann - possibly in part because the extended development time gave more opportunity - really pushed the boat out on the 4-CEP. This model was explicitly positioned as the make or break test case for BR EMU's; and they truly gave it a fair shake in terms of its qualities, at release comfortably the best unit train available in plastic bodied OO.

 

It is a trifle galling that further progress wasn't seen in the BR DMU series, especially as the running gear layout is now about to be clothed in variant 4 when the class 101 is released. All those acres of underside just begging for a concealed decoder location; and the refinement of just one decoder to operate the full set, with independently switched interior and exterior lights. All of which has to be tempered by the fact that they are good models, and were modestly priced when first released. I know I am not alone in thinking that when the basics of the model are so satisfactory, the lack of some small and relatively simple refinements does show up. Perhaps the small increase in price that would result from a slightly superior spec. was felt to be a risk too far?

[stewartingram]

Sorted mine out ok - I removed all the lighting. Much more prototypical for the green era.

 

Stewart

[The Bigbee Line]

Yet they went the full function route with the BP!  I bet there is a simple solution similar to the tweaks to tail lights on diesel locos.  Will have a look when I have a chance.

What's a BP! ?  Excuse me being a bit dim.

[Ray H]

Blue Pullman?

[quattroman41]

After not using my lightweight DMU for a while it refused to move although the internal lights worked.  These I understand are permanently on and cannot be turned off using the function buttons.  I removed the top, tried it again and it moved normally.  Refitted the top and again it would not move.  I changed the chip.  No difference, not working when the top was fitted, working when the top was removed.  I bent the internal light contacts so they would not touch when the top was fitted (no internal lights) and it moved normally.  So now I have a DMU with no internal lights in the power car but at least it moves.  Has anyone else experienced this problem ?  

[Tony_S]

My Derby Lightweight was bought as seen from the Bachmann returns stand. It worked fine on DC (the red/white lights were directional and the interior lights were permanently on). I fitted the 8 pin and 6 pin decoders. Everything was fine until it got to a bend and there was a very nasty smell. Not only had the decoder melted, some of the PCB circuitry had vaporised. The DCC did short out to but not quickly enough! I rewired the PCB replacing the tracks with thin wire and dismantled the motor housing to reveal the bit of bare wire that seemed to have caused the problem. The DMU now works nicely except that the power car has no permanently on lights. The 2 springy terminals don't seem to have any electrical connection to the track pickups. I could restore those too I suppose but I'll wait until I add a driver and passengers!

In fact this is a good time possibly to ask about getting to the drivers compartment. The exploded diagram supplied shows the drivers compartment on the interior floor but on both my driving and trailing car they seem quite firmly fixed in the green body. Do I just have to apply more force or is there a "trick"?

Tony

[HeavyDuty]

Bumping this up as I have two of these inbound and will need to open them up to change destination blinds and add a driver... interested in seeing the answer to Tony's question.

[Holmesfeldian]

How easy is it to change the blinds please ?

 

Any advice welcome, thanks.

Edited May 29, 2014 by Holmesfeldian

[michaelp]

I dont run DMUs but wondered if it would be possible to mount a very small pb or slide switch discreetly on the DMU body to control the lighting?

 

As I said I dont run any DMUs so my knowledge of them is limited.

 

Michael

[mkwolf1877]

Hi everyone

What a nightmare putting decoders into Bachmann derby lightweight dmu got it done but lights in power carriage don't come on.do you have to set the 2 decoders to same address so that the directional

Lights are in sync?, any advice I would be grateful.

Hi,

Did you ever get it sorted?

Mark

[halsey]

Good to find this thread - very helpful as I have the same problem as the OP

 

Had to find it via Google not an "internal" search but that's OK

Edited December 25, 2019 by halsey

[halsey]

Is anyone still watching this topic

 

I have lighting problems with my Bachmann Derby Lightweight DMU the "trailer" interior lights up fine the direction lights work but are the wrong way round?

Bachman mention adjusting CV29 in some way to solve this but the instructions aren't clear so I haven't touched it

The "motor" unit doesn't light up anything at all interior or driving 

The complete coupled unit runs fine and responds to direction speed with the trailer responding to direction changes but neither decoder is recognised through the programme track "read" function but historically I did set them to be the same. (prodigy advance 2)

If anyone is out there any suggestions??

[Nigelcliffe]

13 minutes ago, halsey said:

Is anyone still watching this topic

 

I have lighting problems with my Bachmann Derby Lightweight DMU the "trailer" interior lights up fine the direction lights work but are the wrong way round?

Bachman mention adjusting CV29 in some way to solve this but the instructions aren't clear so I haven't touched it

The "motor" unit doesn't light up anything at all interior or driving 

The complete coupled unit runs fine and responds to direction speed with the trailer responding to direction changes but neither decoder is recognised through the programme track "read" function but historically I did set them to be the same. (prodigy advance 2)

If anyone is out there any suggestions??

 

Motor unit first:   no lights means one of two things.   First, the decoder could be fitted backwards - putting an 8-pin in backwards will give motor control, but no lights, so try turning the decoder plug through 180 degrees.   Secondly it could be electrical contacts within the unit, ie something has become detached. 

 

Trailer unit:   On its own, it is unlikely to be read on the programming track (not enough current through lights to generate the "read" pulse back from the decoder).   So, you'll have to write values without reading, or extract the decoder and put it into a loco with a motor which has enough current to be read.   
One of the features of CV29 is to change which way is "forwards", which will solve the directional lighting issue by "fibbing" which way is forwards for that decoder. 
First, calculate new value for CV29 - use this tool I wrote about a decade ago:   http://www.2mm.org.uk/articles/cv29 calculator.htm    Once you've got the options you need selected, the choice of direction changes things by "1", so there are only two possible values you'll need to try out.

With just the trailer unit on the programming track, write the new value for CV29.  

[halsey]

1 hour ago, Nigelcliffe said:

 

Motor unit first:   no lights means one of two things.   First, the decoder could be fitted backwards - putting an 8-pin in backwards will give motor control, but no lights, so try turning the decoder plug through 180 degrees.   Secondly it could be electrical contacts within the unit, ie something has become detached. 

 

Trailer unit:   On its own, it is unlikely to be read on the programming track (not enough current through lights to generate the "read" pulse back from the decoder).   So, you'll have to write values without reading, or extract the decoder and put it into a loco with a motor which has enough current to be read.   
One of the features of CV29 is to change which way is "forwards", which will solve the directional lighting issue by "fibbing" which way is forwards for that decoder. 
First, calculate new value for CV29 - use this tool I wrote about a decade ago:   http://www.2mm.org.uk/articles/cv29 calculator.htm    Once you've got the options you need selected, the choice of direction changes things by "1", so there are only two possible values you'll need to try out.

With just the trailer unit on the programming track, write the new value for CV29.  

 

THANKS for this - very detailed - I have just come back to my laptop after posting and spending the intervening time working on the problem

Results so far -

Discovered 6 pin decoder in trailer was wrong way round it now reads correctly on the programming track, with a 6 pin Zimo how can you tell the right way round?

All contacts very dirty - I bought this one just before we moved house/storage so have never given it a thorough service - this is now well underway....

Trailer is done except for reversing the lights

Motor underway in terms of cleaning wheels and contacts but I cant get any life out of the lighting but haven't spent much time trying as yet I need to ensure the internal contacts are even "making"

I will try turning the decoder next although I followed a Bromsgrove Models info sheet to the letter as the wires and "packet" do fit much better one way than the other

CV29 issues noted and again will try next time

Many Thanks

 

[halsey]

Just popped to the railway for 1/2 hr and guess what the decoder was fitted 180 deg wrong and the driving lights now work 

 

Why don't Zimo identify/label pin no 1!

 

OK so I now know its the orange wire but if its a decoder without wires there is no clue??

 

I actually like learning by my mistakes - it has its challenges but it makes you think and therefore remember better going forward

 

I didn't have time to check direction or interior just driving lights for now - more tomorrow

 

[halsey]

ALL NOW WORKING CORRECTLY!!

 

Chuffed - 3hrs of back to basics really - clean wheels re-tension and clean all internal contacts check Decoders are fitted the right way round (ZIMO could have made this easier) put it all back together and voila!

 

Bachmann could make these units easier to take apart (my eBay glue spreaders proved really good for this) but I suppose they would look more like toys if they did so its a trade off - also I wish I had noticed that the decoder wires now show in one of the inside (by the 2 car coupling) windows but I'm not taking it apart again!

 

Thanks for all the help and support much appreciated...……………..

[Nigelcliffe]

19 hours ago, halsey said:

 

Discovered 6 pin decoder in trailer was wrong way round it now reads correctly on the programming track, with a 6 pin Zimo how can you tell the right way round?

 

 

13 hours ago, halsey said:

Just popped to the railway for 1/2 hr and guess what the decoder was fitted 180 deg wrong and the driving lights now work 

 

Why don't Zimo identify/label pin no 1!

 

 

Zimo publish an extensive decoder manual, with diagrams, page55 onwards in my English language version.

 

The convention on 6-pin and 8-pin is that pin1 is orange.