lights not working correctly

[tonystrains]

I have a Bachmann 2 car dmu class 105 and using an elite to control. On F0 it turns headlights and interior lights on together instead of just headlights. F1 which should operate interior lights does nothing.Any ideas what if anything i have done wrong or is it a fault .It came DCC fitted from new.

 

[96RAF]

Do the directional lights swap over with change of loco direction and does this have any affect on the interior lights.

 

Do any of the lights respond to F2 or F3.

 

If no separate control of the interior lights possible then I would suspect a wiring fault by the manufacturer.

 

Without taking the tops off and inspecting the wiring I doubt you can go much further, although this is definitely not recommended for a new model which should go back under warranty.

[Chrissaf]

I have a few Bachmann models, all mine came with fairly extensive documentation detailing a function list of what function does what.

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Review your DMU documentation and see it that gives a clue as to whether the interior lights are supposed to be on a different function number or not.

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Specify the Bachmann stock code number it is in the form XX-YYYY for your model, that will help contributors here to do research on your behalf.

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Although I do not have a Bachmann DMU, I do have a Bachmann EMU, for which the Interior Lights are controlled separately on F8.

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Important point of clarification required.

When you say it came DCC fitted from new. Do you mean DCC fitted at the Bachmann factory or DCC fitted by the retailer at time of purchase.

[tonystrains]

Thank you for answers.It was DCC fitted at factory and have had it for some time so out of guarantee. the model is  31-327. it does state F1 for interier lights. The direction lights change with direction of travel but interior stay on.

Thanking you all again for any answers.

[96RAF]

In that case I would take the tops off and remove one decoder at a time and note if that changes anything. It may identify a bad decoder.

 

you could also try a reset on both decoders as the Elite controller allows that And will reprogram a dummy car - see the manual for info.

 

if you can post a picture of the decoders someone may be able to ID them which could help with fault diagnosis, or as you obviously have a PC and an Elite download a trial copy of RAILMASTER and read the decoders using the in application facility.

[Chrissaf]

Bachmann models that are factory fitted with a DCC decoder usually have the letters DC after the stock code number, thus your 31-327 would be expected to have 31-327DC on the box. Bachmann locos with factory fitted 'sound' decoders usually have the DS suffix.

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According to this Bachmann information resource (see page 7 of 76), the only Class 105 they produced DCC fitted around the time of your models production date was the 31-325DC in Blue not Green. The 31-327 in Green is shown as DCC Ready.

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This would infer that your particular model was DCC fitted by somebody in the supply chain other than the Bachmann factory. This puts an element of unknown into the equation regarding who did what & where and what was done to the wiring of your model.

[Fishmanoz]

F1 controlling interior lights is I think unusual. F1 would normally control directional lights ( tell me if I'm wrong someone).  Give Chris's F8 a try.

[Chrissaf]

I only have seven locos (all sound). Mine use F0 for directional lights which I believe is virtually industry standard. F1 for me is 'Sound on/off'. Obviously on 'non sound' locos, F1 could be assigned to anything the decoder manufacturer chooses.

[96RAF]

A standard 3/4 function (depending upon your viewpoint) non sound decoder is F0 (1 function with 2 selections) for directional lights on the white and yellow wires, with F1 on the green wire and F2 on the purple wire with the blue wire as the common positive.

 

F0 is obviously directional whereas F1 and F2 outputs are regardless of direction.

3 Functions that could be seen as 4 if you take the directional F0 as 2 functions (1 each way).

 

However once the tops are off it should be a simple case of chasing the decoder wires to see what they are connected to.

 

Any decoder not conforming to these rules are configurable by Function mapping will have this clearly explained in the blurb. 

[Chrissaf]

So put simply, if Tony traces the Green wire from the decoder (controlled by F1) then this wire (if loco wired correctly) should go to the interior coach lights.

[Fishmanoz]

Apologies for the steer from the nether regions, F0 it is.  And of course Chris's F8 must be from a sound decoder, silly me.  Wire tracing sounds like a good way to go.

[96RAF]

I was reading on another forum of problems on a twin decoder setup and oddly it was capacitors on the motor that were the root cause.

 

even more oddly it was the one without capacitors I.e. The dummy that was giving problems which went away when the capacitors on the other one were removed.

 

the investigation to prove this entailed putting both on the track but separate i.e. Not linked - each picking up its own power, then as the motor car moved away from the dummy car the lights on this one started to behave, so it was put down to some sort of proximity effect.

[tonystrains]

Have taken top of dummy car and their is a pc board with a number of resistors and diode, but the green wire from the socket does not appear to go anywhere. The yellow and white go to the board and the red and black are connected to the wheel pick ups.The interior lights are somehow wired via the resisters and diodes from the yellow/white wires.

[96RAF]

If the green wire isn't connected then it has no effect.

the blue wire must be correctly connected somewhere else the yellow and white ones wouldn't work.

try tracing the cab lights back to the PCB then see if the green wire could be attached to the PCB to link with the appropriate trace point I.e. The switched side not the power side, or if the switched side of the cab lights could be disconnected from the PCB and linked direct to the green wire.

[Chrissaf]

Just to reiterate what RAF is saying, but put another way.

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Currently the white and yellow wires go to your front and rear lamps for the directional lighting. You have identified that the interior lights tee into the white and yellow wires via resistors and diodes on the PCB. The resistors will almost certainly be providing current limitation to protect the lighting LEDs from burning out. The diodes will almost certainly be providing a simple power logic to allow the interior lights to come on whether going forward or reverse and prevent the forward and reverse lamp operation from being compromised at the same time.

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You need to identify a convenient point where you can isolate the wiring from the interior lights away from the existing PCB. Then wire the interior lights to the decoder green wire via a protective resistor (1,000 ohms @ 0.25 Watts should do nicely). The green wire would then be switched negative by issuing the F1 command. The fact that the interior lights are working means that the blue positive wire is already connected OK and shouldn't need to be modified.

[96RAF]

I couldn't have put it clearer myself Chris - in fact I didn't.

 

Thinking about again the cab lights will have to be rerouted from the PCB as they must be linked into the directional lights at present.

[Fishmanoz]

There's another simple explantation here which explains Tony's original observation - the cab lights come on when the directional lights are switched on - and the wiring he's found. Both are consistent with only having a 2-function decoder, a decoder that only operates directional lighting.  You would then use the resistor/diode arrangement from the directional lighting so that you can also have cab lighting, but only when directional lighting is on.

 

So, if it is only a 2-function decoder, there will be no green wire (or purple) to attach the lights to.  But if the decoder is 4-function, even though the loco is designed for 2, then you can do the mod suggested to separate the cab lights from the directional and turn them on and off as you please.

[96RAF]

Well spotted Fishy.

But he says the green wire from the socket doesn't appear to go anywhere not from the decoder, although if Bachmann is like Hornby all the in loco wiring will be black.

More info or a picture needed I think.

[tonystrains]

tried to load up picture to forum page but would not upload for some reason

[96RAF]

If you click on the black and white square icon above and browse to the picture on your pc then click to select it the picture will upload but it will also show a flag that it has to be moderated before it appears on the forum. This can take minutes if Adam is on th eball or days if you post after he has gone home Friday afternoon.

 

I have seen the dialogue say this is taking longer than usual - check this, check that but I reckon that is down to my flaky wireless.