The body is removed from the chassis by splaying it outwards along each side and carefully removing it from the chassis. There are three features per body side that locate the body to chassis. A 21-MTC decoder is mounted correct side up (as shown above). The ESU 11x15mm sugarcube speaker with enclosure is located as shown above. Note that the speaker is under the enclosure. This enables more sound to escape from the model. There are separate solder pads available on the OTM lighting board, or the speaker wires can run directly from the decoder to speaker. Test the decoder and then reinstall the body. Pre-production sample shown above.
Do not remove the couplers. Remove the large screw that the short cab bogie pivots on. Then remove the 6 screws under the trailer floor. The black underbody can be separated from the brown floor of the trailer to access the guard's compartment for decoder installation. Remove the guard compartment floor (brown) with integrated weight as room is required to fit the decoder, speaker and stay alive. The model comes with an 8 pin socket for a decoder. Plug the decoder in, but align the grey decoder wire with the white mark on the socket (usually the orange wire would align with the white mark). Refit everything ensuring any live connections are carefully insulated. Reassemble model and test.
Another well thought out installation design by SRM. Simply splay out the body and lift off from the chassis. Remove the 21 pin dummy/DC jumper board and install the ESU LokSound 21-MTC decoder as shown below. Ensure the 21 pin black header (or yellow "4" on decoder) is facing UP! If it faces down the decoder will short circuit and fail and this mode of failure is not covered by warranty.
The Trainbuilder DERM was specifically designed to accommodate a 16x25mm oval speaker in the #2 end. The speaker should be sealed to its custom enclosure with MicroKrystal Klear. The motor and pickups are soldered in position. The headlights and markers are driven by 4 LEDs, a white and a red LED respectively at each end. The group of transistors and voltage regulator is incompatible with DCC, so require removal from the LEDs. At each end of the DERM, one white and one red LED should be wired in series with one 470 ohm resistor onto one output function from the decoder (yellow -ve for #1 end, white -ve for #2 end). Then the +ve common from the two groups of LEDs is connected to the blue wire of the decoder. A 3 pin micro plug & socket between the decoder and lighting systems enable separation of the body from chassis. The interior lighting comes as a separate system which runs off DCC track power. It can be left alone from the decoder, as there is an on/off switch located under the floor. Hwoever it can be wired inas a separate auxillary function to the decoder via the purple or green wire (-ve) and the +ve will be again the blue common return wire.
Sound installation in the DERM is relatively easy. The large bass reflex speaker is ported for excellent sound reproduction. The speaker has double sided tape holding it to the ceiling of the passenger compartment. The bottom of the speaker box is dead flush with the top of the side windows, so it is out of sight. The LokSound decoder resides in the guard's compartment
The DRC body is removed from the chassis via six small screws under the floor. To keep the passenger compartment free, an ESU LokSound V4.0 decoder and 16x25mm speaker was installed in the guard's compartment. The speaker is sealed air tight to the enclosure and the resultant sound level is appropriate. The lighting has been daisy-chained such the headlights, white markers and opposite end red markers are directionally illluminated with F0. 470 ohm resistors are on each function output (-ve). The interior lighting strip is wired to Aux 1, which is activated via F11. Front and rear pickups are isolated from the motor, and the motors grey and orange wires are direct soldered to the respective wires on the decoder. Finally the body is reassembled to the chassis and the DRC is ready for service, with authentic sounds from DRC 40.
This has to be one of the most simple of sound decoder installs. The rail car comes truly sound ready, and the best effort we've seen to date, when it comes to good design. A 20mm 4 ohm 1 Watt speaker comes pre-installed in the fuel tank area. The speaker is wired back to the 21-MTC plug, so it's a simple matter of installing the decoder once the body has been removed. The installed decoder is a tight fit against the inside bulkhead which houses the exterior fans. The lightboard may need to be unscrewed from the interior and moved 1 or 2mm forward, toward the driver's cab.
Note the decoder orientation! DCCSound does NOT warrant decoders which have failed due to improper connection to the 21-pin socket. Take care and double check the pins aren't out by one row. If the decoder is mounted incorrectly and powered up, it will most probably fail immediately.
Disconnect the trailers from the power unit, via plugs located in the ends of the trailers. This makes handling easier. The 21-MTC plug is located within the power unit. The power unit's body is removed from its chassis by splaying the lower sides outwards, and gently removing the powered chassis. The chassis has four decent sized lugs which retain the body. A speaker can be mounted inside the roof of either passenger compartment. The passenger compartment body is removed from its chassis by gently splaying out the lower edge of the body from the chassis, after removing the coupler of course. In the image below, the two speaker wires need to be soldered to the small PCB, where 'SPK' is printed. A small amount of CA glue is used to temporarily hold the speaker in place and Krystal Klear is use to seal up the speaker to enclosure. Unfortunately the speaker is positioned such that the sound cannot escape all that well from the compartment, but it is what it is, and we are satisfied with the overall volume from the model as viewed on a large layout - it's appropriate.
Note: Handle the 21 pin decoder with care - avoid electrostatic discharge to the decoder during handling, and ensure it is inserted correctly (refer to image of decoder mounted, as below), as incorrect insertion voids the decoder's warranty. If the decoder is not recognised, check that the 21 pin plug hasn't broken away from the PCB, as a couple have been received like this, ex factory.The pseudo couplers are very small so take care of them.
Modification to PCBA for twin speakers (one speaker per trailer):
Blue wire and orange wire added such the speakers are wired in series. Do not wire the 4 ohm speakers in parallel. If wiring speakers in parallel, ensure they are at least 8 ohms.
Note: Trailers must be correctly connected to Power unit (e.g. First class to First class) otherwise the track power will go directly to the speakers.
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NAB, BSB 083-532, ACC 196544471
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