Amy&Elke

  Fitting lights to locos


Handy parts
Fitting front light Darjeeling 'B'
Fitting back and cab light Darjeeling 'B'
Fitting lights to Amy, Elke and Irene
Replacing SMD transistor when blown-up after short-circuit


Handy parts

Parts
NL DE UK Conrad #
PTFE wire 0.7mm Ebay Ebay Ebay n.a.
Heat-resistant cable 1mm Conrad-NL Conrad-DE Conrad-UK 603204
Enamelled Copper Wire 0.5mm Conrad-NL Conrad-DE Conrad-UK
605544
Copper-paint wire black 0.15mm Conrad-NL Conrad-DE Conrad-UK 242531
Micro Bulb 3.2mm 6V 115mA Conrad-NL Conrad-DE Conrad-UK 1218713
Micro Bulb 3.2mm 6V 70mA Conrad-NL Conrad-DE Conrad-UK 720086
Micro Bulb 3.2mm 6V 40mA Conrad-NL Conrad-DE Conrad-UK 720072
Shrink wrap 1.6mm Conrad-NL Conrad-DE Conrad-UK 1318263
Shrink wrap 2.4mm Conrad-NL Conrad-DE Conrad-UK 1318264
Shrink wrap 3.2mm Conrad-NL Conrad-DE Conrad-UK 1318265
Socket strip 2 pin Conrad-NL Conrad-DE Conrad-UK 1498257
Socket strip 3 pin Conrad-NL Conrad-DE Conrad-UK 1498258
Brass rod 1mm Conrad-NL Conrad-DE Conrad-UK 297208
SMD transistor PBSS4350X Conrad-NL Conrad-DE Conrad-UK 1112944

Use the PTFE wire as the standard cable: it withstands the heat, is small and strong. The heat resistance cable 1mm is an alternative.
When size matters use either the enamelled copper wire or the very small black copper-paint wire. The last is only 0.15mm in diameter and very suitable for wiring that is in sight (but keep both wires to the bulb under 300-500 mm long to limit voltage drop).  The insulation of both rely on a thin outside layer that is easily scratched when fitting. So always check with a voltmeter whether you have caused a short-circuit! To remove the outside layer before soldering either use your solder iron on a temperature above 385 °C or remove the layer with a sharp (hobby) knife.
Real light bulbs are strongly preferable above LEDS as they - despite using more current – do give a light quality that fits the atmosphere of old steam locos much better. And they better do survive high temperatures of a live steam loco (LEDS are rated upto 80°C only). The advised micro bulbs are all 6V and run on a 4.8V battery: a lower voltage considerably increases the life time of the bulbs. When your loco has one front or back light only use a micro bulb of 115mA or 70MA. When the loco has 2-3 front or back lights use 40mA micro bulbs. For the cab light use a 40mA micro bulb.
Shrink-wrap is a special rubber tube which reduces in diameter when heated. Use a hair drier or similar to shrink the shrink-wrap and it will close tightly around the wire (if nothing else is available hold the flame of a gas lighter close by).
The socket strips are needed when connecting to a Riverdale Telemetry Receiver.
The brass rod comes in handy when fitting micro bulbs in a Darjeeling cab.
The listed SMD transistor is a replacement part for the Riverdale Telemetry Receiver in case the SMD transistor is blown up after a short-circuit.


Fitting front light Darjeeling 'B'

Next is described how a working front lamp is fitted on my prototype Darjeeling 'B'.
On the smoke box boiler band (top) make an indication for a later cut-out just behind the M2 screw of the RH lamp unit. Now the RH lamp unit, sand box, saddle tank, boiler band and the brass strip 1.5*0.5mm have to be removed from the loco. The brass strip can be put aside as it will not be used anymore. At the earlier made indication, make a cut-out in the boiler band with a flat needle file of about 1.5*1mm. Check pictures below for the correct position.
Now prepare the light bulb unit. Cut the lamp wires to a length of 6mm. Prepare 2 lengths of enamelled copper wire 0.5mm, 122 and 128mm long. Remove insulation layer from all 4 ends over a length of 4mm, tin the wires and solder them to the micro bulb. On one wire slide a length of 8mm shrink wrap 1.6mm up to the bulb. Shrink the shrink wrap. Make a second length of 18mm shrink wrap 1.6mm. It goes over both wires up to the earlier fitted shrink wrap. Shrink it. A length of 10mm shrink warp 2.4mm goes over both wires and both earlier fitted shrink wraps up to the bulb. Shrink it. Finally a length of 15mm shrink wrap 1.6mm is fitted like in the picture below right.

Front bulb assembly
Light bulb unit

This light bulb unit is fitted to the loco instead of the brass strip 1.5*0.5mm. With a pair of pliers pull on the wires sticking out one by one until the 0.5mm copper wire and the last fitted shrink wrap are pulled tight against the boiler as in the picture below. Check that boiler band cut-out and boiler band opening (where the M1.6 screw sits) coincidences with both left and right shrink wraps of the light bulb unit. Else slide the copper wires over the right shrink wrap until this is the case.

Front bulb  as fitted
Light bulb unit fitted to the loco just before rotating the unit upright

When all OK slide the light bulb unit upright and fit the boiler band. Bend the wires like in the left picture below. The RH lamp unit can now be eased over the light bulb and fitted with the M2 screw.

Front light
End result after fitting boiler band (left) and RH lamp unit (right)

To make the connection with the receiver, solder 2 PTFE wires 35cm long to the enamelled copper wire under the smoke box and use some shrink wrap for insulation. Route the PTFE wires over the wrapper screws, over the last boiler band screw and through the hole in the inner frame. Slide some 8mm shrink wrap 1.6mm over the wires. Solder a 2 pin socket strip onto the wires. Shrink the shrink wrap.
With a Voltmeter test that there is no sort-circuit to any metal parts of the loco. Try the lamp with a 4.8V battery and enjoy the end result.
From experience I know that using 1mm Silicone or 0.7mm PTFE wires instead of copper 0.5mm wires will not work.
When the smokebox door is already fitted it's not necessary to remove it.


Fitting back and cab light Darjeeling 'B'

Start with preparing a micro bulb frame and a guidance piece. Both will be used to route the wiring later. Use the PDF drawing in link as guidance to bend both parts from 1mm brass rod. Open the PDF file, print the drawing at 100%.
Now prepare the back light bulb. Cut the lamp wires of a 6V 115mA or 70mA micro bulb to a length of 7mm. Prepare 2 lengths of PTFE wire both 300mm long. Remove insulation layer from all 4 ends over a length of 4mm, tin the wires and solder the wires to the micro bulb. Do not use too much solder. On one wire slide a length of 10mm shrink wrap 1.6mm up to the bulb. Shrink the shrink wrap. Make a length of 10mm shrink wrap 2,4mm. It slides over both wires up to the micro bulb. Shrink it. Finally make a length of 8mm shrink warp 3.2mm and shrink it over the previous fitted shrink wrap against the micro bulb. The upper 8mm should now fit nicely into the 4mm lamp hole and the lower 2mm in the 3mm roof hole.
Next prepare the cab light bulb. Cut the lamp wires of a 6V 40mA micro bulb to a length of 6mm. Prepare 2 lengths of PTFE wire both 230mm long. Remove insulation layer from all 4 ends over a length of 4mm, tin the wires and solder the wires to the micro bulb. On one wire slide a length of 10mm shrink wrap 1.6mm up to the bulb. Shrink the shrink wrap. Make a length of 10mm shrink wrap 2,4mm. It slides over both wires up to mico bulb. Shrink it.
The mico bulb is fited to the bulb frame with a length of 10mm shrink wrap 3.2mm according to the picture below. Take note that the frame is not symmetric and that the bulb slides over the shorter end. Finally a length of 8mm shrink wrap 1.6mm is fitted holding both wires against the frame like in the picture.

subassemblies
Micro bulb frame with cab bulb fitted, guidance piece and back light bulb

Remove the Darjeeling lamp from the roof. Guide the wires of the back light bulb from above the roof through the 3mm hole until the bulb fits into the hole with the last 2mm shrink wrap. Fit lamp, guidance piece and M3 screw. The soldered on piece of 6.5*4mm brass prevents the wiring sticking out from under the roof. Make two lengths of 15mm shrink wrap 1.6mm and shrink these around both wires and the 1mm messing rod of the guidance piece according to the picture below. While shrinking, cover the painted roof with some cloth and paper to prevent it getting damaged by the hot air necessary for shrinking.

Back bulb wiring
Darjeeling lamp, guidance piece and back light bulb with wires fitted

Make a length of 15mm shrink wrap 2.4mm and slide this over the bulb frame starting from the free end without bulb. Ease it over the 90° corner which needs some fiddling and twisting of the shrink wrap. Next push the 2 wires from the cab bulb through the shrink wrap. Now position the earlier prepared roof plus micro bulb frame like in the picture below. Put the bulb frame on top of the roof and push the 2 wires from the back light bulb through the same shrink wrap. Make sure you make a nice not too large S-shape as in the picture. You may have to twist and torque the wires quite a bit to route them nicely against the roof. When satisfied shrink the shrink wrap. Finally shrink a sort piece of shrink wrap close to the corner of the micro bulb frame. Again cover the roof while using the hot air gun.
Slide a piece of 30mm shrink warp 2.4mm over wires and brass rod and another piece of 30 mm shrink wrap 2.4mm over the 4 wires only. Do not shrink these!
Solder the wires onto a 3 pin socket strip; one wire from each microbulb is soldered to the mid pin. Do not forget to slide pieces of 8mm shrink wrap 1.6mm where applicable. Shrink the shrink wrap. It should look now as in the picture below (3 pin socket strip not shown).

Bulbs ready to fit
Roof with all micro bulbs ready to be fitted to the body

The roof with the micro bulbs is now fitted to the body. The brass frame sits simply pressed under the hinges of the roof. Fit the hinge one side at the time while pressing the brass frame at that side under the hinge. Endresult see picture below. Check the roof opens as it should. Try the lamps with a 4.8V battery and enjoy the end result. The wiring to the receiver goes directly down just before the hinge and then inside the room where the receiver sits.
wiring roof
Roof with its micro bulbs fitted to the body



Fitting lights to Amy, Elke and Irene

A good way to go is to use Roundhouse cast whitemetal loco lamps. To fit a bulb 2 holes need to be drilled like in drawing below. Start with the 3.5mm hole. Use a drill stand and make sure that you clamp the whitemetal lamp while drilling. The lamp glass is cut from a thick plastic see-trough cover. Round 6.5-7mm will do. This 'glass' is fixed to the whitemetal lamp with a minimal amount of 2k glue after painting. Paint the edge of the plasic 'glass' black after fitting. Remove any spillage on the front surface with white (cleaning) spirit (check beforehand whether the plastic 'glass' survives this treatment).
Solder two lengths of black 0.15mm copper-paint wire to the micro bulb. Remove the outside layer before soldering as decribed on top of this page. Shorten the bulb wires to 3mm beforehand so all soldering stays invisible inside the whitemetal lamp. Apply several layers shrink-wrap 3.5-4mm long to end up to a diameter that just fits in the newly drilled bottom hole of the whitemetal lamp (similar to the Darjeeling lamps described above). Finally simply slide the bulb in the bottom hole. Try-connect the wires to a 4.8-6V battery and enjoy.
lamp RH
Adapted Roundhouse cast whitemetal loco lamp fitted with a microbulb


Replacing SMD transistor when blown-up after short-circuit

This replacement could be necessary after a sort-circuit of one of the light outputs. You need to have experience with soldering electronic components: the SMD components used are very small. Remove the top end part of the plastic casing as in the picture below. The 3 transistors that control the front, cab and back lights are now visible. These PBSS4350X SMD transistors do have 4 connection leads. The top connection lead and the middle of the 3 bottom leads are interconnected. For removing, all 3 bottom connections need to be heated at the same time by your solder gun. It's wise to pre-heat the top connection first. When the solder is melted, swipe the blown-up SMD transistor out of the way. Solder the replacement transistor in its position. Use some tape to cover up the casing.

receiver transistor replacement
The 3 SMD transistors are visible to the right


Return to Riverdale receiver page

© 2017 Riverdale Locomotives