Hornby R3270 MML HST Wrong Direction Lights

[Sir TophamHatt]

Quick question.

 

My MML HST motor car reverses when the controller is FWD selected.

Obviously runs in conjunction with the rear power car and the lights.

It's a socket.

Normally I'd just change CV29 but I don't want to break the lights at the other end.

 

I need to do a spot more testing but I guess it isn't just the chip that's the wrong way is it?

Edited March 28, 2019 by Sir TophamHatt

[RAF96]

If the lights are working OK now then reversing the decoder plug will make them broken, so you have the choice of reversing the config in CV29 or swapping the yellow and white wires over at the errant car socket if the motor direction  and lights do not match.

If the direction is wrong but the lights are in synch with the other end then swap the motor wires.

Edited March 27, 2019 by RAF96

[njee20]

Break it down a bit, because I'm not clear from the OP exactly the problem, and swapping wires around will cause other issues if nothing's broken.

- if the lights are correct for the direction of travel (ie white forward, red backward) but the direction is the opposite to intended AND both power cars are in sync (ie one always shows red and one white lights) then put both power cars on the program track and change CV29 (adding one if it's even, subtracting one if it's odd)

- if the above is true but the power cars both display the same lights then only do this to the motorised power car

- if the lights are correct but the movement is wrong (ie it's showing white lights when going backwards) then you need to swap either white/yellow or grey/orange wires, again if this is both power cars then do it to both, this is unlikely to be the issue unless someone's been messing before, and will not fix the problem if it's either of the first manifestations

[RedgateModels]

of course if you have a decoder that allows function mapping you can swap the value in CVs 33 and 34 to reverse the operation of the lights

[Sir TophamHatt]

Sorry, I could have explained better.

 

It's the DCC Ready HST so I don't really want to go swapping wires around inside.  It's strange though as I would have thought it would work with the motor car leading as standard.

 

The lights work in the correct way, IE, white when the motor car is leading/pulling, red on the rear dummy and vice versa if I select the other way.

 

However on the controller I have to select 'Reverse' to have the motor car pulling.

 

I don't mind swapping the dirction in CV29 but do I do this with the power car and the dummy seperately, or both together?

[NoelG]

7 hours ago, Sir TophamHatt said:

Sorry, I could have explained better.

 

It's the DCC Ready HST so I don't really want to go swapping wires around inside.  It's strange though as I would have thought it would work with the motor car leading as standard.

 

The lights work in the correct way, IE, white when the motor car is leading/pulling, red on the rear dummy and vice versa if I select the other way.

 

However on the controller I have to select 'Reverse' to have the motor car pulling.

 

I don't mind swapping the dirction in CV29 but do I do this with the power car and the dummy seperately, or both together?

Ah that sounds simple just change the direction bit in CV29 if the lights and motor direction are in agreement. If the dummy car has its own decoder than both separately, otherwise just the power car on the programme track (ie assuming some sort of electrical connection for the lights between the dummy and power car

Edited March 28, 2019 by NoelG

[Sir TophamHatt]

But as it's a DCC ready loco, I would assume this shouldn't be the case?

Or could I have wired my track wires the wrong way?

[RAF96]

1 hour ago, Sir TophamHatt said:

But as it's a DCC ready loco, I would assume this shouldn't be the case?

Or could I have wired my track wires the wrong way?

 

 

DCC is effectively AC so there is no wrong way, except if linking certain DCC things together when you have to match polarity (actual match phase). Swapping your track wires over will make not one jot of difference.

[Sir TophamHatt]

Right.

But I still don't understand why Hornby would wire it up wrongly, and why there's not loads of reports of this if they did?  Perhaps mine is one of a kind that is just wrong?

[peach james]

If you have to select reverse to run forward, then it means that the programmed value of CV 29 does not match the left/right rail setup of the electric motor.  That's all.  It could be a 1 off, or it could be that for most people, the value of CV29 isn't a hard to change thing... or they don't know any better/don't care.  (I try to avoid having backwards locos, as it makes it far more entertaining when running with DCC- but almost all of mine are wired backwards for DC, and just software altered to run the "right" way around...)

 

It's not hard if you have any sort of programmer, or you can use a CV 29 calculator to figure out the correct values.   I recommend a programmer like SPROG or (in my case) Digitrax PR3, and Decoder Pro.  Makes it just checking boxes to get the settings you want.