Rail truck with Loksound decoder question for Mr. Bachmann

[prompter]

Mr. Bachmann,

I have installed 2 Loksound 3.5 decoders in 2 different 0n30 Rail trucks. Both installations exhibit the same problem. When starting, there is a slight pause, then the truck jumps ahead then resumes normal speed. When stopping, the truck slows to a stop, then jumps ahead.

When I move either decoder to the On30 Gas-Mechanical, everything works correctly.

I suspected that the problem with the rail trucks (both) might be capacitors or RF chokes on the PCB board (per the note included with the rail trucks) , but according to Bachmann tech support they no longer include capacitors and chokes on the boards. I could not locate any obvious components on the board, but did note a label for L1 and L2.

I question this answer, and wonder if this problem could be raised within Bachmann?

Thanks.

[the Bach-man]

Dear Prompter,
I'll see if anyone has anything to offer...
Thanks!
the Bach-man

[David(UK)]

Any item in a cct board with an L designation can safely be assumed to be a Choke or inductor.
If in doubt, carefully cut one leg of the component in such a manner that you can reconnect it if a trial run proves negative.
Regards
dAVID(uk)

[daveb]

I have a Rail Truck with exactly the same problem, but it is hardwired so there is no Bachmann PC Board to cause the problem. After attempting to adjust the BEMF operation by means of its CV's my only solution was to turn off the BEMF on the Loksound decoder, which does improve the stopping and starting jerking. I have previously asked for advice on the Loksound Yahoo Group but received no help.

Remember that cutting the inductor leads on the Bachmann board will stop anything from working, they need to be bridged out for any test, while the capacitor leads need cutting.

Dave

[prompter]

DaveB,

Nice to know someone else has the problem -- I thought perhaps I was seeing things... It's interesting to know that the problem still exists when the decoder is hardwired, but no problem in the Bachmann Gas Mechanical.

I seem to recall a discussion on some board about the rail truck having some component located near the motor, not on the PC board.

Any info on that possibility would be helpful.

Thanks,
Chuck

[Tim]

Prompter , DavidB

I have two of the trucks \, and I found that the power pickup
on the front truck is very delicate and prone to being intermittent.

I doubt that your decoders are at fault, if you have the decoder that
came with the model, try that and see if it works any differently.

I also checked my exploded views and there are no electronic components
anywhere except on the circuit board.

Tim Anders
Souderton, PA

[daveb]

I have 3 of the Rail Trucks, 2 fitted with Soundtraxx decoders and one with Loksound.  The problem only occurs with the Loksound not with either the original Bachmann or the Soundtraxx decoders, which leads me to believe that the problem lies with the BEMF settings. The Loksound manual refers to their website for recommended settings but they are nowhere to be found.
I have completely disassembled one of my units and unless something is hidden within the motor, which I doubt due to its small size, there are no electronic  components other than on the pcb as you noted.

Dave

[prompter]

I guess I don't understand why BEMF would react differently on the rail truck and the gas mechanical. The Loksound decoder has been reset to factory defauts (CV 8 =8) before testing in both the truck and the GM.


Chuck

[Tim]

Prompter

On your Gas Mechanical , is the circuit board intact?

The "Digitrax" decoders are designed with any filters buffers built in
for the american market.

The "LokSound" decoders are designed and built in europe.
they may need the components you removed to function correctly.

Just wondering.

Tim Anders
Souderton, PA

[prompter]

Tim,

The circuit boards on the GM and both rail trucks are stock - no changes, nothing removed. all work correctly with the stock decoders. Both rail trucks fail the same with either loksound decoder. The GM works correctly with both loksound decoder. Go figure. 

BTW,  Bachmann tech support has referred me to Lee Riley. I've left him a VM.

Chuck

[Tim]

Chuck

Your last post leads me to believe that there is an unwanted current path
in the trucks possibly intermittent.

I will spend some time analizing my trucks tomorrow.

Will post if I find anything.

Tim Anders
Souderton, PA

[prompter]

I changed CV  49 to 2 (BEMF off) on one of my rail trucks, and it is now working correctly.

Chuck