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Converting ditch lights on Atlas Master™ Series HO Dash 8-40BW and Dash 8-32BHW Locomotives so they can be controlled on DCC separately from front headlightThere are two steps to converting the ditch lights on an Atlas Master™ Series HO Dash 8-40BW or Dash 8-32BHW locomotive so that they can be controlled separately from the front headlight on layouts that are equipped with DCC:
PLEASE NOTE: Once the rewiring described in this procedure has been completed, the ditch lights will no longer operate at all on conventional DC (analog) layouts. In order to operate the ditch lights, it is necessary to run the locomotive on a layout that is equipped with DCC. WARNING: Unless you are experienced in, and comfortable with, wiring to small delicate electronic circuit boards, Atlas strongly urges you to find someone who does have such experience to do the necessary re-wiring for you. Many local hobby shops are either able to perform such work for you or else can recommend someone who is proficient in this type of work.
Perform the following rewiring steps in the order indicated: 1. Unscrew the front and rear couplers and coupler pockets from the locomotive and remove them. Put all of the small parts that you removed in this step into a covered plastic box (or some other place) for safekeeping until you are ready to reinstall the body shell on the locomotive frame. Then, using tweezers or very small needle nose pliers, carefully remove from the rear left-hand (fireman’s side) truck side frame the brake cylinder that holds the bottom end of the brake chain. The brake chain is the short length of chain that runs between the body side sill and the truck. 2. Remove each half of the fuel tank by pulling it out sideways (i.e., away from the center of the locomotive frame). Again put both parts of the fuel tank away in a safe place. Next carefully remove both sets of long and both sets of short side handrails from the holes in the cab casting into which they are inserted. Failure to remove these handrails from the cab casting can result in their breaking when you pull the body away from the frame. 3. The Dash 8-40BW and Dash 8-32BHW hood castings each have three pairs of rectangular tabs that project downward from the bottom of the casting. Each of these six tabs has a horizontal slot in it that is designed to fit an inward facing horizontal projection on the die cast locomotive frame. The Dash 8-40BW or Dash 8-32BHW body is held onto its metal frame by inserting the six projections on the frame into the six horizontal slots in the plastic tabs on the hood casting. Thus to remove the body from the frame, it is necessary to release all six of these frame projections from the slots in the tabs on the hood casting. The two rear-most projections on the frame casting are located just above the rear axle on the rear truck. The two middle projections are located at the center of the recessed portion of that part of the frame from which you removed the two plastic fuel tank halves in Step 2. The two front-most frame projections are located where the side sill widens on the left (fireman’s) side of the locomotive. To remove the body casting from these projections on the frame, you have two choices:
In many cases, a combination of the above two methods will work best. 4. After you have squeezed the body or pushed inwards on the tab (or pair of tabs), pull upwards on the hood casting and wiggle until the hood has been released from that projection or pair of projections. Release the body from the frame projections one pair at a time and work from the rear pair of projections, to the middle pair of projections, and (finally) to the front pair of projections. After you have removed both the body and the side sill castings from the frame, set these body parts aside in a safe place. 5. Cut the four wires (two red and two black) that run that run from the two centermost wire connection tabs at the front of the Atlas #342 HO Dual-Mode® Four-Function DCC decoder to the two sets of silver-colored ditch light connection pads that are located on each side of the locomotive frame, near the front of the frame. Make these cuts with a small fine-tipped flush-cutting shear or rail nipper (such as one of those made by Xuron). Make sure that you cut each one of these four wires as close as possible to the place where the wire is connected to one of those two centermost tabs at the front of the decoder. Also make sure that you do not accidentally cut any of the red and black wires that run to the LEDs used to illuminate the front number boards and headlight. 6. Extend each of these four wires by soldering to them short (1 ½ inch long) lengths of 26 to 30 gauge insulated stranded wire. TIP: It is easer to solder the extensions onto the existing wires if you do NOT cut the extension wire to the specified length of 1 ½ inches until AFTER you have soldered the connection between the original wire and the new extension. The factory wiring convention used in these Dash 8-32BHW and Dash 8-40BW Locomotives is (except for the black wires that run to the trucks) every red wire is connected to a positive terminal, and every black wire is connected to a negative terminal. Observing this same color convention during your re-wiring will greatly simplify future troubleshooting. Hence, it is strongly recommended that you extend each wire with another piece of wire that has the same color (red or black) as the wire that you are extending. One inexpensive source of such wire is a package of Model Power No. 2302 2-conductor hook-up wire. In this particular Model Power wire, one of the conductors has red insulation, and the other has black. If you use this wire, separate the red wire from the black wire by cutting (with a hobby knife that is fitted with an Xacto or other No. 11 blade) between the two wires for about ¼ inch and then pulling the two wires apart until you have about fourteen inches of black wire and fourteen inches of red wire. TIP: Make sure that no exposed copper wire shows through the insulation (on the side where you have separated the two conductors) on any length of wire that you intend to use for this conversion.
Procedure for programming the CVs of the DCC decoder in a rewired Atlas Master™ Series HO scale Dash 8-40BW or Dash 8-32BHW Locomotive to allow independent DCC control of ditch lights WARNING: The ditch light rewiring that was described in the preceding procedure MUST be performed BEFORE attempting the CV programming described in this procedure. Put your modified locomotive onto your DCC programming track and perform the following CV programming steps in the order indicated: 1. Set CV53 to get the type of ditch light operation that you desire:
2. Set the DCC function that you wish to use for turning on and off the ditch lights by writing the same numeric value into both CV54 and CV55 for continuously illuminated ditch lights or into only CV54 for alternately flashing ditch lights. If you number the bit positions of these CVs from 8 to 1 as you read from left to right, the ditch light or lights will be controlled by function Fn whenever a binary “1” is written into bit position n. For example, if you wish to use DCC function F2 to turn on and off alternately flashing ditch lights, you would write the binary number 00000010 (or its decimal equivalent “2” for those DCC systems that accept only decimal CV values) into CV54. Alternatively, if you wish to use DCC function F3 to turn on and off continuously illuminated ditch lights, you would write the binary number 00000100 (or its decimal equivalent “4”) into both CV54 and CV55. 3. Remove your locomotive from the programming track. 4. Place the body back onto the frame, after first making sure that the front of the body is on the front of the frame. Then push down firmly on the roof sections of the front hood, the cab, and the rear hood until the body is seated securely onto the frame. Make sure that the brake chain does not get caught between the locomotive body and frame castings when you are pressing the hood onto the frame. 5. Then put the locomotive onto your main track, and check for proper ditch light operation. 6. If everything checks out OK in Step 5, reinstall the fuel tank halves, the couplers, the long and short handrails, and the brake chain that you removed at the beginning of the ditch light rewiring procedure. |
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