Converting an old LGB split gear box to DCC

[mbendebba]

Hello Folks:
I am looking for ideas on how to isolate the motor from the track in an old lgb split gearbox, an old 2040 croc to be exact. I have been unable to find anyting in the decoder fitting compilation. I have an idea on how to do it, but would like to hear how other have done it. I have decided on a Massoth XLS decoder for this croc.
Cheers

 

[steve parberry]

when i did ine i soldered two wires to the motor tabs and coveredd with heatshrink tube to act as an insulator also bent the tabs away from the other contacts.. sorry no picks though.

 

[muns]

Mohammed,

check out the decoder compilation thread for usefull ways of doing things (including split gearboxes) http://www.gscalecentral.net/fb.ashx?m=1252

I soldered directly to the motor and covered the insulated with several layers of heatshrink when I dropped a decoder into my old 2095.

 

[Zerogee]

It's quite easy, I've just done exactly that on both bogies of an old 2095.

The screws that hold the gearbox halves together are all on one side. You need to gently remove the wheels ONLY on that side (catching the pickup brushes as they try to spring out of course!), then remove the screws and lift off the gearbox half. Now, very carefully lift out the motor, being sure to catch the small ballbearings embedded in the grease at both ends of the motor shaft. Now, if the loco is too old to have the three-position isolator switch, the motor will not have any wires attached to it, but if the loco is slightly newer and has the switch, like my 2095 did, it will probably have one wire already attached to the motor via one of LGB's standard push-on connector terminals. Obviously you need wires on BOTH motor terminals, so you will need to solder either one or two on, covering the terminals with heatshrink at the same time. If you want to keep to LGB's colour code, then the two motor wires should be yellow and green. Now, in both halves of the gearbox there is the brass contact bus that connects the wheel pickups, skates etc; that has a vertical sprung strip that makes pressure contact on the motor terminals - if your motor had no wires already attached then there will be a contact strip in both gearbox halves, but if the motor already has one wire attached then the contact strip on that side will have been removed at the factory. Either way, you need to SNIP OFF the contact strip(s) to the motor - I've found that if you use a good pair of small side-cutters, you can actually get in there and snip the brass without having to completely remove the contact bus from the gearbox housing. Once this is done, then the motor ois electrically isolated from all the track pickups. All you need to do then is carefully reassemble the gearbox, remembering to put all the bits back where they came from, and leading the one or two new wires out through the top of the gearbox - you might need to snip away a few little bits of plastic to route the wires easily, and/or drill a small hole, as you prefer - just make sure that the wires don't get trapped and prevent the gearbox halves from mating properly.
Now, as it's from a two motor loco, both gearboxes will probably already have two track power wires attached (my 2095 had them soldered to the little brass pads that are visible at each end of the assembled gearbox) - these should be brown and white by LGB's standard wiring code. With the green and yellow wires from the now-isolated motor, you now have a four-wire gearbox ready to connect to the decoder!

I hope that makes sense, sorry that I don't have pics (I was so busy doing the job on the 2095 that I forgot to take any!) - but anything else, please ask!

Jon.

 

[mbendebba]

Thanks steve, mark, and Jon. I dismanted the gear box prior to posting my question. The biggest concern I had about the conversion was how to get the 2 new motor connection wires out of the gear box without interfering with the motor. It is still a concern but knowing that a few had done it give me the impetus to go ahead with the project. I will certainly take pics. Thank again.

Cheers

 

[Zerogee]

Mohammed - do your Croc motor blocks have the little brass contact tabs at the end of the top surface, which may or may not have wires soldered to them, used for supplying track power to the loco body internals, lights etc? If so, there is a small gap between these two brass tabs, and you can usually lead the motor wires out through here after carefully snipping away some small notches of plastic from inside the gearbox to allow the wires to reach the gap. if you bend the new motor leads straight up after soldering them to the motor terminals (or indeed solder them on pointing upwards, at 90 degrees to the motor shaft instead of parallel to it), there should be plenty of room for them without them going anywhere near the worms or axle gears.
There is actually more space than you think inside the gearbox housing, and nibbling away at some of the plastic areas with a good pair of fine snippers will usually make suitable spaces to route wires through - just be careful that you don't cut away anything that is needed to keep things in place (like the brass bus strips) or as an insulating spacer (some bits of plastic are there to keep the track pickups on each side from touching each other!).

Jon.

 

[whatlep]

Hello Folks:
I am looking for ideas on how to isolate the motor from the track in an old lgb split gearbox, an old 2040 croc to be exact. I have been unable to find anyting in the decoder fitting compilation. I have an idea on how to do it, but would like to hear how other have done it. I have decided on a Massoth XLS decoder for this croc.
Cheers

Have a look at the pictures in my recent thread here: http://www.gscalecentral.net/m160892 . They should help.

 

[Zerogee]

Very useful pics! Mohammed, if you look specifically at the seventh photo down of Whatlep's other thread, the one that shows the motor: where the blue wire has been badly "pinched" right above the motor terminal - you need to snip away a little of the plastic at the top of the motor cradle just where this wire runs over the top of the motor, to give it clearance and avoid the pinching that has happened in this case. Not much, just a nick out of it to take the thickness of the wire.

Jon.

 

[mbendebba]

Mohammed - do your Croc motor blocks have the little brass contact tabs at the end of the top surface, which may or may not have wires soldered to them, used for supplying track power to the loco body internals, lights etc? If so, there is a small gap between these two brass tabs, and you can usually lead the motor wires out through here after carefully snipping away some small notches of plastic from inside the gearbox to allow the wires to reach the gap. if you bend the new motor leads straight up after soldering them to the motor terminals (or indeed solder them on pointing upwards, at 90 degrees to the motor shaft instead of parallel to it), there should be plenty of room for them without them going anywhere near the worms or axle gears.
There is actually more space than you think inside the gearbox housing, and nibbling away at some of the plastic areas with a good pair of fine snippers will usually make suitable spaces to route wires through - just be careful that you don't cut away anything that is needed to keep things in place (like the brass bus strips) or as an insulating spacer (some bits of plastic are there to keep the track pickups on each side from touching each other!).

Jon.

Jon:
you touched on just about everything that I have concerns about with this installation. You are right about the space, it does look small on first take, but on subsequent takes in does seem to get bigger. As long as I stay away from the worm and the gears, I will be fine. I will ckeck and re-ercheck before I close the gear box.