Bachmann class 40 lights question

[dj_crisp]

hi

 

Daft question. I have a set of Bachmann light boards for a class 40 from their latest model (nose and cab lights) to fit to an older 40 and thought I'd hard wire them into a dcc decoder. Do I need to include resistors as I'm not sure if they're already on the light boards?

 

Thanks

Will

[tractor_37260]

On 25/08/2020 at 10:02, dj_crisp said:

hi

 

Daft question. I have a set of Bachmann light boards for a class 40 from their latest model (nose and cab lights) to fit to an older 40 and thought I'd hard wire them into a dcc decoder. Do I need to include resistors as I'm not sure if they're already on the light boards?

 

Thanks

Will

 

Hi Will

           As nobody has yet commented, here's my tuppence worth.

There are resistors on the nose boards, but Bachmann also sometimes fit additional resistance in the +comm track on the main circuit board.

When I discard the factory main circuit boards when fitting EM2 speakers on 37's I fit resistors between the decoder outputs and the nose end contacts , your cab lights will require resistors also.

Factory lights as supplied tend to be over bright, so the resistors will help reduce their brightness AND also help protect the LED's (a belt and braces approach)

 

So yes resistors on all decoder - neg output wires- White/Yellow/Green/Purple etc  680ohm to 1Kohm resistors being suitable. 

HTH

Ken

 

 

Edited September 9, 2020 by tractor_37260
correct text

[dj_crisp]

19 hours ago, tractor_37260 said:

 

Hi Will

           As nobody has yet commented, here's my tuppence worth.

There are resistors on the nose boards, but Bachmann also sometimes fit additional resistance in the +comm track on the main circuit board.

When I discard the factory main circuit boards when fitting EM2 speakers on 37's I fit resistors between the decoder outputs and the nose end contacts , your cab lights will require resistors also.

Factory lights as supplied tend to be over bright, so the resistors will help reduce their brightness AND also help protect the LED's (a belt and braces approach)

 

So yes resistors on all decoder - neg output wires- White/Yellow/Green/Purple etc  680ohm to 1Kohm resistors being suitable. 

HTH

Ken

 

 

Hi Ken

 

Very useful info. I think to be on the safe side I'm going to wire in some resistors.

 

Cheers

Will