Bachmann Std 3 tank (31-981) & chip (36-553) - fits but help needed with settings

[Alex TM]

Hi everyone,

 

Sorry if this sounds a daft question, but will the Bachmann standard 8-pin chip (36-553) chip fit their standard class 3 tank (31-981).  I have the loco, but don't want to go and buy their chip if it doesn't fit.  I know there are smaller chips available from other manufacturers but I am trying to keep all of the decoders from the same make.

 

Thanks in advance for any help offered.

 

Regards,

 

Alex.

Edited August 26, 2018 by Alex TM

[Butler Henderson]

Have 2 3MTs one with a Bachmann decoder in it and the other a Lenz Standard.

[RFS]

As B-H says above, a Lenz Standard+ fits perfectly and is a much better decoder than the Bachmann one. 

[Alex TM]

Hi again,

 

Thanks for the information.  I've used Lenz decoders when I first tried my hand at DCC, and never had a problem with them.

 

Regards,

 

Alex.

[Alex TM]

Hi again everyone,

 

The good news is that the Bachmann chip fits; the tricky bit is getting the wiring loom as far into the smokebox/boiler as possible.

 

The bad news is that the running is poor, as it takes off at 'high' speed and is a bit noisey too; it was fine on analogue.  Curiously it does not run on analogue either.

 

I realise that I'll need to change a cv setting to sort the latter out, but does anyone have any advice on settings and values to deal with the former?

 

Again, thanks in advance for any help or advice.

 

Regards,

 

Alex.

Edited August 26, 2018 by Alex TM

[JST]

What setting is CV3? I tend to set mine to 015 and the loco takes off nice and gently (it may sit for a few seconds before it decides to move).

[Alex TM]

Hi again,

 

No idea what the current value is but I'll try your suggested setting and let you know how I get on.

 

Thanks,

 

Alex.

Edited August 26, 2018 by Alex TM

[Butler Henderson]

This may be of use despite the model not being listed

http://service.Bachmann.co.uk/wp-content/uploads/2018/02/decoder_settings.pdf

 

Assuming I have not tweaked mine elsewhere this is the Decoder Pro data for it

 <CVvalue name="1" value="3" />
      <CVvalue name="2" value="1" />
      <CVvalue name="3" value="0" />
      <CVvalue name="4" value="0" />
      <CVvalue name="5" value="7" />
      <CVvalue name="7" value="88" />
      <CVvalue name="8" value="151" />
      <CVvalue name="17" value="199" />
      <CVvalue name="18" value="222" />
      <CVvalue name="29" value="38" />
      <CVvalue name="49" value="1" />
      <CVvalue name="51" value="1" />
      <CVvalue name="53" value="0" />
      <CVvalue name="54" value="12" />
      <CVvalue name="55" value="63" />
      <CVvalue name="63" value="1" />

[Alex TM]

Hi again everyone,

 

First of all, thank you for all the help, ideas, and supportive approach with this.  Although I have played with DCC before, I had never taken programming beyond address and direction change.  Tonight I had to 'bite the bullet' and start playing with CV settings.  The bad news was that some of the setting suggested here made no difference.  I then reset the chip - again, no difference.

 

Now, the good news; I found the following thread:

 

http://www.rmweb.co.uk/community/index.php?/topic/45821-Bachmann-36-553-decoder/

 

There was a post on there about back emf and the relevant CVs; this 'rang a bell' in respect of something I had seen elsewhere (but now cannot find).  I changed these as follows, based on suggestions from Bachmann about the Std cl4 2-6-0 - CV 54 to value 12, and CV 55 to value 63.  What a difference!  Crawls gently and smoothly; there is no erratic speed change, noise, and it performs equally well in both directions.

 

82021 is now back in its box however I did forget to deal with the analogue running.  Ah well!

 

Thanks and regards,

 

Alex

[34theletterbetweenB&D]

...82021 is now back in its box however I did forget to deal with the analogue running.  Ah well!...

That may be doing you a favour. Some users have reported in the past that having analogue operation available on this decoder can lead to unreliability and random loss of address.

 

I have had very good service from these 36-553/554 decoders in large motor+flywheels mechanisms - mostly diesel models on my operation - for which the BEMF constants in CV's 54 and 55 were set near optimally as factory default.

 

I would have used these decoders more widely when they were a very cheap option - circa £10 - £12 - had they only had more extended range in CV's 3 and 4, as I want values up in 100s with steam locos to reflect their very extended accelerations in the slow low power to weight ratio and low brakeforce situation particularly affecting unfitted freight. One thing I did find with smaller motored models, especially Bachmann, was that sometimes there was considerable sensitivity to small changes in CV's 54 and 55. You might be able to squeeze a little more running refinement yet out of the model with some experiment.