Help with shorting LGB Spreewald

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tim stevens

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Hi. I have just reconverted my LGB Spreewald from Battery back to DC/MTS. As usual this wasn't without its problems. Having removed the batteries and motor controller from the cab I managed to pull off the wires that are connected to bulbs that light up the single rear light at the back of the cab and the light inside the cab. I also reinstalled the plunger pickups, unaware that this could be done without removing the chassis and ended up getting very conused as to the position of the pick up springs (which connect the six wheels for the plunger pickups, and the motor pickup wires (which connect to a 4 pin sockit). In the end I used the 2 long wires on the exterior attached directly to the axle and the 2 short ones on the interior ( god knows what they do but I suspect it is something to do with the plunger pickup!). The explosion diagrams provided by LGB are next to useless and rather frustrating. I then did a quick solder to reattach the light wires and found that my locomotive will not run properly in reverse (1/4 speed at best) but was fine going forward. Also the switch inside the cab seems to be doing the same thing regardless of its settting. Can anyone help. I have now disconnected the cab and wires and the problem still persists. I am pulling my hair out and quite honstly I dont have a lot left. Hope someone out there can help.
 
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I have now done a bit more exploring and have come to the conclusion that the MTS chip may well be fried. If I remove the main power cable (4 wire cable connected to the wire pickups from the wheels) to the circuit board of the Spreewald (22741) then the locomotive runs fine on 12v dc. I am still concerned about the arrangement of springs and pick up wires which feed the circuit board from the plunger skate pickup and the axles. Does anyone out there have a photo of this so I can make sure all is right here. I notice that the motor pickups and rail pickups are not isolated which seems odd but I do not really understand the LGB circuit board. The cheapest option to me seems like converting to dcc using a Uhlenbrock 77100 which I have on some marklin maxi locomotives rather than trying to find another circuit board. I can isolate the motor and rail pickups relatively easily but I was a bit worried about the lights and whether the bulbs could handle the dcc voltage from the decoder. Any help here would really be appreciated
 
Hi Tim
This is the pick ups on my Spreewald showing clearly what should go where. Hope this helps.
Steve.....P1040185.JPG
 
tim stevens said:
I have now done a bit more exploring and have come to the conclusion that the MTS chip may well be fried. If I remove the main power cable (4 wire cable connected to the wire pickups from the wheels) to the circuit board of the Spreewald (22741) then the locomotive runs fine on 12v dc. I am still concerned about the arrangement of springs and pick up wires which feed the circuit board from the plunger skate pickup and the axles. Does anyone out there have a photo of this so I can make sure all is right here. I notice that the motor pickups and rail pickups are not isolated which seems odd but I do not really understand the LGB circuit board. The cheapest option to me seems like converting to dcc using a Uhlenbrock 77100 which I have on some marklin maxi locomotives rather than trying to find another circuit board. I can isolate the motor and rail pickups relatively easily but I was a bit worried about the lights and whether the bulbs could handle the dcc voltage from the decoder. Any help here would really be appreciated
Click to expand...

Hello Tim,
This sounds really odd, unless I've misunderstood what you're describing.... if you pull the main black 4-pin connector plug off the gearbox unit, are you saying that the motor still runs when you apply power to the wheels and/or skates? If so, then somehow the power pickups have become connected directly to the motor connections..... In order to get the gearbox unit to run without the black connector in place, you SHOULD have to connect the four pins on the gearbox with jumper cables, linking each outer pin to its corresponding inner pin. Without such jump connections there should be no way that power can get from the wheels to the motor, unless something has been badly misconnected inside the motor block!

Don't worry about the voltage for the lights, you can turn that down by altering a CV on the decoder - but of course you do need to remember to do this before putting the loco on track power for the first time after installing the decoder!

Jon.
 
Hi Nemo and Steve thanks very much for the replies. Yes i thought it was odd but the 2 outer pins (of the 4) connect directly (rub against it) to the motor terminals. I cant see any other way of fitting the motor without this happeningthe pins or the motor without this happening. I also have enclosed pics of the pickups which are probably also wrong.

IMG_20170111_153732100[1].jpg IMG_20170111_154336030[1].jpg IMG_20170111_154343150[1].jpg
 
Hi Jon (Zerogee). Just realised the last comment should have been addressed to you. As you can see from photo 1 the outer pins connect directly with the motor terminals and the inner and outer pins on the pickup side seem to be connected as well so yes the the motor is connected directly to the pickups!!! What have have i done wrong.It must be the pickup assembly that is wrong as I cant see any way of fitting the motor without the two outer pins touching the motoer terminals!
 
Tim
The two inner pins are the power supply from the track, via the wheels, bullets and the long bars that run the length on the chassis, also touching the skate cross plates. The long bars are pressed onto the skate plates when the bottom cover is screwed on. The two outer pins are the input to the motor and connect with the motor pins inside the block as you describe. They are bent over underneath as can be seen quite clearly in my photo and DO NOT touch anything. This is probley where your problem is, make sure the two outer pins are not touching anything underneath, they should just touch the motor terminals and be fed from above via the connecter.
 
Hi Steve. Thanks very much for that. Just a couple of extra questions. Should the 2 inner pins where they turn over be under or above the skate cross plates. ie do the long bars that provide the wheel connectons sandwhich the inner pins between the skate plates or do they sandwich the skate plates between the pins (ie are pins on the bottom or in the middle (like the picture )IMG_20170111_170859965[1].jpg
hope this makes sense.. For some reason when I put the assembly back together I seem to get a short between one side and the motor pinand cannot work out why. Both the outer pins are clear of the skate plates. Thanks again. Tim
 
Thanks Tim. Yes, as you've spotted and Steve has confirmed, the motor terminals ARE supposed to touch the outer two pins; what there is NOT supposed to be is any connection between the outer pins and the inner ones, unless you connect the pins with jumper wires. The purpose of the 4-pin connector plug is to take the power input from the wheels/skates (the inner pins) to the decoder, then the output of the decoder back via the outer two pins to the motor.
There is obviously something wrongly connected inside your gearbox, though I can't see from the photos what it might be. Whether this will have damaged the decoder, you will only know when you've traced the fault and put it back together, you might be lucky and have got away with it, or there is a possiblity that the output transistors may have been fried...... is there any sign of melting on any of the decoder components, or any trace of a "nasty electrical smell" that indicates that some of the Magic Smoke has escaped....?

Jon.
 
It might be worth noting that the long connecting bars have to be fitted facing the right way, they will go in the wrong way round and then everything goes haywire.
It wasn't a Spreewald, I think it was one of my Corpets, but hey, I'm stupid. :fubar:
 
Skate plates on the bottom, then the pins then the bars, all gets compressed together when base plate is screwed on (you can just make this out in me photo.
 
Tim. Your photo shows the inner pins under the stake plates - this is probably causing the unwanted connection to the outer pins.
 
Thanks for that guys. I will change the skate plate arrangement as it is clearly wrong in my picture and check that the motor terminals are isolated from the wheel and skate pickups and then fit a new decoder. I have learned an important lesson which is not to rip the loco apart when fitting a battery/deltang unit and not really knowing how to put it all back when I change my mind!!. Thanks again.
 
tim stevens said:
Thanks for that guys. I will change the skate plate arrangement as it is clearly wrong in my picture and check that the motor terminals are isolated from the wheel and skate pickups and then fit a new decoder. I have learned an important lesson which is not to rip the loco apart when fitting a battery/deltang unit and not really knowing how to put it all back when I change my mind!!. Thanks again.
Click to expand...
Sound practice is to take a Digital Pic as you deconstruct, that way you have a reference should you wish to retro engineer the job.
JonD
 
The other way you get track to motor shorts, is if the long springy connecting bars are in the outer positions, rather then the centre positions, as they should be..
Don't ask!
 
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