LGB 10340 Shuttle Unit

[Madman]

It's been one of those days. You know, the ones that happen when your trying to show your trains and their operation. I know a few weeks ago, someone posted a problem with their 10340 shuttle unit. Well, today one of my shuttle units started to act up. It's behaving like there is a short somewhere. I checked the track wiring, and the wiring to the unit from the power pack. I could not find any problems. When I turn the power on to the track, the loco moves an inch then stops. It may do this one or two more times, then nothing, until I cut the power for a short time, then power up again. Then it does the same thing. As it was getting too dark to do any more investigating, I 'll get back to it tomorrow. I plan on disconnecting the wiring to the track and try looking for a short on the track with a continuity tester. The funny thing is the shuttle worked perfectly when I re did some of it's track work last week.

 

[beavercreek]

Mine used to do that because I was using a loco that was drawing too much power (in excess of about 1 amp). The unit cannot pass through the power and sort of shuts down, resets, shutsdown, resets etc so the loco 'bunny hops' down the line. It sounds like maybe the loco has starting to draw extra power or or a sound board or extra lighting in a car is maybe to blame (if the exact consist is as was working perfectly before).
I solved my problems by getting 5 amp shuttle units although one of those has started to go strange on me.

 

[Philbahn]

Like Mike says have you checked the loco on a different track..Found dodgey motors do that

 

[Madman]

I am only running an LGB hand car. It works perfectly on any other track. I also tried an LGB tram loco. Same thing with the herky jerky dance on the shuttle track. I was under the assumption that the 10340 could handle more than one amp.

 

[beavercreek]

. I was under the assumption that the 10340 could handle more than one amp.

It is a 1 amp unit (well 1.25 to be precise).
When the 'bunny hopping' happened on my shuttle it was only due to the loco drawing too much for the unit. What you are running should be fine. Perhaps there is something on the line which might be drawing a little current? Can you measure a current draw from power pack to shuttle line with nothing on it? If not then you probably do have a defective unit

 

[Madman]

Yes, I measured the voltage and it starts out at lets say 12 volts at the track, then goes to 0 volts after a second or two.

 

[beavercreek]

Yes, I measured the voltage and it starts out at lets say 12 volts at the track, then goes to 0 volts after a second or two.

Just to make sure that your power pack is fine. Could you test the line with the reverse unit out of the equation and feed from just the powerpack. I am not sure what power system you are using but the voltage to zero effect occurred on a failing Train Engineer receiver of mine. It is probably not your pack but it is best to eliminate it from the possible problem.
If the line and power is fine with no possible shorts etc. Then the last thing that could be wrong before blaming the shuttle unit as the culprit is a dodgy diode (although this should not really create an effect like you have). Once the power pack has been tested and is fine, test the line diodes by putting the multimeter set to OHMS before and after the diode. with the probes one way there should be total resistance, the other way should show a measurable resistance (on my meter it is about 490 to about 600 ohms on all my shuttle diodes). Then test them with voltage applied to the track. Before and after the diode - depending on the way around the probes are applied you should get full voltage one way and none the other!
Another even better way to test is by using an actual loco on the track - still without the reverse unit and power straight from the tranny (or receiver in my case) put the loco in the middle of the shuttle line, apply power and it will go to the end of the line (if it does not move, reverse the polarity of the track) when it gets to the end of the line it will stop once it has crossed the diode gap. Reverse the polarity to the track and it should start back down the line and do exactly the same at the other end where you again reverse the polarity to the track and it should go off again. If this happens then the diodes are perfectly fine.
Re attach your reversing unit. Try the same loco. If it does not move , reverse the polarity of the power pack to the reversing unit. If it does not move or bunny hops then it does look like the unit is up the creek.
I hope this helps.
My 5 ampo reverse unit seemed to be playing up (a loco was going through the diode and carrying on!) but under test all diodes are fine, weith another loco the unit was fine so the culprit was the loco. I had been added a sound board to the loco and had not been careful enough and the wiring which had somehow caused the loco to waft through the diode gap.:wits:

 

[minimans]

Yes, I measured the voltage and it starts out at lets say 12 volts at the track, then goes to 0 volts after a second or two.

You really need to measure the current draw not the voltage, use an amp meter in line with one of the feeds to the track, anyone will do it will just show amps as + or - but the number will be the same. This will give you the amp's being used, anything above .5amp for Gus on his trailer is too much...............Paul...........