Recently a member pointed out that the photos were no longer available in my early forum topics moved over from G Scale Mad. I'll attempt to remedy this over the next few days, starting with this topic as a Moderator managed to fix the ones in the sound storage topic.
[h4]Posted by: fnrobinson Sep 4 2008, 12:50 AM[/h4] First remove the four screws (two each end) from the buffer beam and then lift off the buffer beams,
?cos if you don?t you won?t be able to unscrew these four!
Now remove the four longer and larger diameter screws from alongside the bogies
and finally the four from the fuel tank. These are the same diameter of those alongside the bogie, but longer.
Ease the body away from the chassis, it?ll need a little bit of jiggling to get the cab internals free from the crew seats, especially the one the drivers sitting in. Now unplug the wiring connectors to completely separate body from chassis.
The internal wiring is simple and easy to work out, no circuit board.
Rather than use a proprietary kit I decided to add rear lights my way. You could just add white leds to the red lenses, but I decided to replace the original white leds with brighter ones and use the originals for the rear, red, lights. As the loco would be analogue only I wired the leds in inverse parallel pairs. This means that the current flows through one led of each pair with the polarity one way and through the other one when the polarity is reversed. If you wanted to go digital the leds would be wired independently and connected to the appropriate decoder terminals.
To access the lower leds remove the piece of tape sticking them down to the channel in the cab console assembly, ease the body sides outwards and pull the console assembly backwards. Once this is free carefully remove the clear plastic led holder by pushing on the lenses through the cab front a little at a time. If you try and push one side out completely before starting on the other you?ll increase the chance of breaking it. If it does snap just weld it back together with your soldering iron.
Make a note of the wiring colours and remove the wires to the leds in the clear plastic holder. If you do this one at a time you can always compare it to the original, or the one you?re just done. Put the new leds in the holder with the flats in the opposite direction to the existing ones. Bend the new led leads to touch the old ones on their outsides. This, IMHO gives enough stability and distance to obviate the need to insulate them. Note, as mentioned earlier, in this picture the original led has been moved to the red position and replaced by the new led in the headlight position.
Here?s an assembly with one new led wired up to an original with the other as yet untouched. Once this is done repeat for the other side and then the other end.
Now remove the blocking diodes that are part of the original set up. I?ve done four of these locos, on the earlier three there was one diode at each end of the loco, but on the latest there were two per end.
With the ones on the chassis side you can just resolder the wires together.
On the body I decided to fit the inverse parallel diode for the top headlamp between the position of the old blocking diode and the top side of the relevant resistor. Ensure the diode is the opposite way round to the top headlamp led. You could use the original blocking diodes or new 1N4004 or similar, they?re only a matter of pennies each.
When you?ve checked the modifications reconnect the body and chassis wiring and test the lights before final reassembly of the loco. Reassembly is pretty much the opposite of dismantling, just make sure that number one end of the body (it should be marked inside the cab roof) is at number one end of the chassis (usually marked on the frame and it should be the end with the driver fitted). Also remember there are three different sizes of screw, detailed earlier, and that the fuel tank only fits one way due to the spigot on the body.