Bachmann Junior Locos DCC Fitted

[HLT 0109]

I have just acquired second hand locos no 49 "Stuart" 0-6-0 and no 31 "Greg" 0-4-0.  Both are marked DCC Fitted and are hard wired.  I immediately placed each of them on my programming track (NCE Powercab) and keyed in "Use Programming Track" whereupon the message appeared "Short Circuit Detected".  I immediately switched the power off and then switched it on for my layout -  with the locos on the track, no short was detected.  Next I reverted to the programming track and tried again - "Short Circuit Detected".  This time I pressed OK and a message appeared asking if I still wanted to proceed.  I did so in order to give each loco its new address.  The system could not read the existing addresses but did accept the new ones, after which the locos ran normally on the layout.

 

I tested the programming track with other locos and it worked properly.  Can anyone tell me why this happens and whether I can overcome the problem?  I should be grateful for any guidance.

 

Harold.

 

 

[RFS]

My first thought would be that the decoders fitted to these locos do not support read-back of CV values, so when your Powercab tried to do this, and it failed, it then assumed there was a short.

[Butler Henderson]

The decoders are pretty poor, if anything like the ones in mine they are consist of two separate pcbs! I disposed of them, the locos had come in a set from Modelzone sale and once I had sold off everything else the locos were free. Both initially recieved Lenz Standards but Greg had now become a Arc Models Bonnie Prince Charlie with a hard wired DCC concepts direct plug in decoder.

Edited January 19, 2014 by Butler Henderson

[HLT 0109]

Thank you gentlemen.  At least there does not appear to be anything electrically wrong.  I will consider changing the decoders - Greg in particular rather appeals to me.

 

Harold.

[AndyJH]

My first thought would be that the decoders fitted to these locos do not support read-back of CV values, so when your Powercab tried to do this, and it failed, it then assumed there was a short.

Ive had the same issue, and had been searching today for a solution. Ive decided to replace the encoder altogether, although im some what confused as why the Junior has 3 wires going to the motor, any idea why this would be?

[HLT 0109]

I bit the bullet this week!  Having spent the last 18 months tweaking CVs and thinking I have improved things, only to be disappointed; endlessly re-cleaning wheels and track with the same result, I decided to follow Butler Henderson's example and replace the decoders with Lenz standard decoders.  I didn't want to pay out for anything too expensive in case I made a pigs ear of it.  Stuart was a doddle - everything came apart easily giving clear access to the motor and the pickups; it went back together easily and there was plenty of room in the cab for the decoder.  It now runs very sweetly.  It remains a mystery as to why these locos are fitted with an extra pcb in the roof and have a third wire to the motor housing (something to do with the interference suppression?) but they do not have them any more.  Greg was more of a problem.  I had to split the boiler casing along the top seam in order to access the motor and then it became more of a fiddle to put back together.  Now I have discovered that I forgot to refit the whistle!  Having got it back together, it still ran like a bit of a dog.  The problem was that the pickup design is different from Stuart's and it is (a) very difficult to get them behind the wheel flanges when refitting the chassis and (b) almost impossible to see them when it is all back together.  In the end, the problem was found to be that some of the pickups had distorted and were sitting on top the wheels, where they were making only intermittent contact.  Now they are located properly, the little loco runs quite well.  Having very small wheels and only four of them, Greg does stall at slower speeds on some of my insulfrog points but I am pleased I have made the modifications as I was keen to see how an 0-4-0 performed on my layout.  I do however find CV table in the Lenz instruction booklet unintelligible.

 

I hope this tale is of interest to someone.

 

Harold.

[ovbulleid]

Hi, I’ve just found this thread as I have a 4-wheel junior engine which I am looking at converting to one of the Arc models’ 0458 locomotives. I’ve stripped the engine down and located the pre-fitted chip, can I just remove this and replace it with a simple Hornby 4pin chip (with the plug removed)? Or do I have to wire the chip in amongst the Bachmann chip? And if that is necessary, what order would the chips go? Many thanks

[Butler Henderson]

Hi, I’ve just found this thread as I have a 4-wheel junior engine which I am looking at converting to one of the Arc models’ 0458 locomotives. I’ve stripped the engine down and located the pre-fitted chip, can I just remove this and replace it with a simple Hornby 4pin chip (with the plug removed)? Or do I have to wire the chip in amongst the Bachmann chip? And if that is necessary, what order would the chips go? Many thanks

You only need one decoder

 

Pick ups >>>> Decoder >>>> Motor