Large Scale Central

Bachmann trolley, what standard and what decoders?

General Discussion
#21

Greg Elmassian said:

Stan, the NMRA spec has places where the function of certain pins is optional.

So, can you state (officially or unoffically) if the Peter Witt car meets the NMRA or MOROP standard? From my preliminary research they are NOT identical. I know you stated the European RailCommunity specification, can you provide a link, and also how does this relate to MOROP or NEM?

The web site description does not reference any standard.

The documentation on the electronics likewise references a 21 pin decoder, but again no standard is referenced.

This makes it difficult for someone to choose a decoder, and also ensure it will work.

I’m investigating a problem and this is my next step in determining the path to follow in further debugging.

Regards, Greg

Greg

Any official information on a Bachmann product can only come from Bachmann. If you need anything from Bachmann, I suggest you call them or post your question on their forum.

The MTC21 interface is currently used in both Marklin 3 rail and DCC 2 rail applications. Several of the pins are only used for Marklin installations which can cause confusion for normal 2 rail DCC installations.

None of the DCC decoders use these 3 rail pins that I am aware of.

The MTC21 interface was developed by ESU and was updated several years back to change from a 100 ohm speaker to an 8 ohm speaker.

The NMRA S-9.2.1 document contains several differences from that currently used by both the DCC decoder manufacturers and the locomotive manufacturers. The most notable are that AUX3 and AUX4 should be logic level outputs. From discussions held last week I expect the NMRA will update S-9.2.1 to reflect what is currently being used this fall.

The ESU version 4.0 MTC 21 sound decoder and the Lenz 21 pin non-sound or SUSI decoders use this updated specification as do most of the locomotive manufacturers that use this interface.

I have not tested the Zimo decoder but from their web site the MX631C or MX632C non-sound SUSI decoders or the MX644C sound decoder should work.
The Zimo WWW site has the following warning "WARNING: in any cases a “C-type” should be used instead of a “D-type”, because Logic level outputs for FA3, FA4 are needed, especially locos from: Märklin, Trix, LS models, …:

The Bachmann Peter Witt assumes a logic level for the AUX3 output and will have an inverted effect if a non logic AUX3 output is used.

Hope that helps.

Stan

#22

That DOES help Stan, I’m investigating, but have been looking at a sound decoder, the MX644D… it appears that one side of a keep alive capacitor could be connected to one of the optional pins.

Let me come back with some intelligent questions on this, and would you mind helping me since you understand this interface better than me?

Will help everyone I believe, nice to know what does and does not work in this locomotive.

Greg

p.s. still would like a definitive reference to the standard you referenced.

#23

David, thanks for the response, was on the previous page and I missed it.

It’s clear that many manufacturers only test even DCC ready locomotives with a socket on DC only. Witness the recent debacle of the Dash 9 sockets that were all wrong and had to be replaced. Worked fine on DC… did not even work with Revolutions plugged in.

QC is a very difficult thing to enforce with manfacturers in China, you need to spell out exactly what and how things are checked, and then you will pay extra, that is for sure.

Regards, Greg

#24

Greg Elmassian said:

That DOES help Stan, I’m investigating, but have been looking at a sound decoder, the MX644D… it appears that one side of a keep alive capacitor could be connected to one of the optional pins.

Let me come back with some intelligent questions on this, and would you mind helping me since you understand this interface better than me?

Will help everyone I believe, nice to know what does and does not work in this locomotive.

Greg

Greg

Be glad to help if I can Note the Zimo D version is not recommended per the Zimo website. I have no experience with this decoder.

Please note that the following pins have no connection inside the Peter Witt

1,2,3,4,5,6, 17

When you use a suitable decoder is simply plugs in.

Stan

#25

Yeah, the D was the one tried, have to look to see if there is a C version.

on this page: http://www.zimo.at/web2010/products/lokdecoder_EN.htm

the 631D seems to be the same recommended for the MTC interface as the 644D

can you indicate where Zimo does not recommend the 644D?

for those following, 631D is not sound.

Thank you for the NC list, that helps.

Will do some more investigating.

Greg

#26

Greg Elmassian said:

Yeah, the D was the one tried, have to look to see if there is a C version.

on this page: http://www.zimo.at/web2010/products/lokdecoder_EN.htm

the 631D seems to be the same recommended for the MTC interface as the 644D

can you indicate where Zimo does not recommend the 644D?

for those following, 631D is not sound.

Thank you for the NC list, that helps.

Will do some more investigating.

Greg

Greg

http://www.zimo.at/web2010/products/lokdecoder_EN.htm

press the + key to expand the: “MTC” (21-in) direct decoders

press the + key to expand the: Information about the 21-pin “MTC” direct plug-in “D” type decoders and “C” type decoders and their application

I have no experience with the Zimo MTC21 versions and have no idea which locomotives that use Aux3 or Aux4 have full voltage outputs.

Stan

#27

OK, the sentence you must be referring to is:

WARNING: in any cases a “C-type” should be used instead of a “D-type”, because Logic level outputs for FA3, FA4 are needed, especially locos from:

Märklin, Trix, LS models, …

I’m sure the translation is not perfect, the word “any” must be incorrect…

this is the single reference I can find… this is what you are referring to, right?

Thanks again,

Greg

#28

If you look back Greg I think Stan quoted that same line almost verbatim.