LGB throttle problem; anybody had this?

[RH Prague]

Hello everyone..

First real run of the summer. At first I thought my U class had a problem, but not so; the ubiquitous LGB throttle is delivering less power to all locos in one direction (i.e turning the throttle to the left, rather than the right).
If anyone has any thoughts on what this might be, I'd be very grateful for some suggestions. I would not dare to open up the box myself, but my brother in law would.


Thanks in advance,


Richard

 

[stevelewis]

Please advise which LGB Throttle you are using ( Article number if possible)

But in the meantime try reversing the cables which feed the track ( ie change the one from the righthand side of the output on the throttle unit to the left and vice versa) then see if the slowing down has changed to the opposite direction. the right not the left or it stays the same.

ALSO IF YOU HAVE A VOLTMETER may be worth reading what the Max voltage reading is in each 'direction'

 

[minimans]

Be Carefull!!! I have had this when a diode is burning out in the directional lighting it will cause a partial short in one direction only until it burns out altogether!!...........Paul..........

Ah! I re-read your post and it's doing it to all loco's? I would set up an isolated test track and connect the offending transformer to that and recheck your loco's, if there ok on this it means the problem is track related and if they still act up? find your brother in law!!

 

[RH Prague]

Hi Steve and Paul,

Thanks very much for your quick replies.

The throttle is the 52120 model. On the underside is a gold sticker with the number 001075. Bought new early in 2007.

I have switched the wires, and now the problem is reversed, the slower speed is in the opposite direction.

Unfortunately I dont have a voltmeter, but for sure my BIL wil have one. Are you thinking about voltage drop? I have read about it but I still am not sure if I'd know it when I experience it (rather like corked wine). But I should mention that the one throttle and transformer controls all the track, through one connection to the track.The initial total track distance was around 40 metres, but I have recently increased this to around 60 metres. Yesterday was the first full run after the new section was completed. But I thought voltage drop is something that shows up a long way from the connection from throttle to track. I don't have that problem. The speed is consistent around all areas of the system, allowing for gradients of course.

It may not be so simple to set up a test track, so I'd be pleased to hear what you make of the above, and what next steps you'd recommend.

And many thanks again

Richard

 

[Neil Robinson]

Your results confirm your suspicion that it is the throttle that is at fault.
The voltage drop in this question is the internal one inside the throttle. For example if the output voltage is consistently 0.7V less in one direction than the other for the same movement of the control knob it would suggest one diode or other semiconductor junction may be shorting out.

 

[stevelewis]

The Signal Box control unit!

Made in 2005,

It should have given you well over 3 years use without becoming faulty, If it works OK in one direction then there is nothing incorret with the track or connections I think!
It would appear there is an internal fault which has occured to cause voltage drop in one direction.

If the problem can not be identified , or can not be easily fixed, there are a couple of things you could do:

Obtain a 52121 throttle unit ( thats the electronics which go inside the 55120 complete with control knob etc) and replace the faulty one with it,
Or far less expensive use a double pole (DPDT) switch in the output leads to the track to reverse the direction of the current and just use the controller in the 'GOOD' direction.

f room.The DPDT switch could be mounted within the signal box controller as there is plenty of space
Click the thumbnail pic to enlarge!