Fitting DCC Directional Lighting to Bachmann Class 166 FGW

[franco330]

Like many other modellers, I wanted to upgrade my Bachmann 31-028 Class 166 FGW DMU to DCC with correctly operating front and rear lights. Upgrading the 3-car unit (centre) power car to DCC is straightforward and covered elsewhere. What is less straight forward is organising the front and rear lighting to change direction and to remain on when the DMU is stationary; to me this was important but is a personal judgement.

This document illustrates the key decision points and builds on the body of general knowledge already available in this area but specifically for the Bachmann Class 166 and presumably is equally valid for similar DMU sets.

Having searched around I found the best reference to be by Phil Dennison of Aliso Viejo, California which is lodged on the TCS website.

http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/HO_Scale/Mehano/Thalys_T675/Thalys_T675.html

Phil's article describes the integration of direction lighting to an HO Scale Mehano Thalys T675 but offers a very simple way of achieving the right result. I used Phil’s method and modified it to suit the class 166. His insight for me is essentially to splice in the decoder between track power and LED feeds, and with clever CV management has the lights stay on when the DMU is stationary, reverse with DMU direction, and to have control over brightness. Lights on/off is under F0. I followed his recommended CV settings and tuned CV133, but despite having researched what I can, I still have no idea how this bit of magic works. CV 61 and 133 are manufacturer specific as far as I could find out from the NMRA site.

Method: I opted to re-use decoders in the centre car and for one end unit consequently I felt I could buy a new decoder for the other end unit. This overcomes the difficulties of wiring between cars at a reasonable cost. I re-used a TCSDP2X and bought a new DCS T1. Having proved the concept with the TCSDP2X and an 8 pins socket from www.petersspares.com I felt it safer to stay with TCS – see magic above. I would use wired decoders always in future because the final package is neater.

There is some debate with respect to whether the DMU was ever fitted with incandescent lighting thankfully mine is LED see Fig 1.

Steps

• Remove the chassis releasing two screws and unclip the body; disconnect the lighting connector.
  
• The feed from the track (blk/red) to the PCB can be seen and the to the LED cluster can be seen (blk/red).
  
• Cut the feeds from the track. Note the red/blk positions on the PCB
  
• I had to extend the wires to offer more work space. To do this remove the bogie (one screw) and extend using twisted wire/ solder/ heatshrink. Replace bogie.
  
• Take red/blk wires from the decoder and join to the red/blk from the track
  
• De-solder the red/blk ends from the PCB and replace with org/gry from the decoder respectively. See Fig2. and 3
  

Then:

• Reconnect the lighting connector and take the car to yr programming track.
  
• Program all three cars separately with the same address.
  

I used Phil Dennison’s settings blindly: cv 61 to value 68, and cv133 (light intensity) to a value between 0-255, he chose 100, I settled on 50 for the class 166.

Move to yr track. To complete the unit test select yr car address, make sure F0 is on and try changing loco direction, the lights will change. Magic.

Put the DMU set together and check direction and lighting. You may need to turn the power car around to sync direction; the DMU runs all on the same address, not a consist.

Note: Provided you are consistent with the mapping of wires through from track -> decoder -> PCB -> LEDs for both each end car I the lighting should work correctly - one end red when the other is white. If it doesn’t, I found the quickest way to correct this was to swap the orientation of the lighting connector.

Apologies for large images,, better next post - good luck