# Using MRC DCC Sound Decoder on Analog Power ONLY?



## Jerrys-RR (Jun 21, 2010)

About half of my LGB locos came with decoders and about half did not. The nice thing is that they all work just fine with plain old track power because it has been well over a year since I last tried to use MTS or DCC. I've forgotten most of what I know about MTS/DCC and I don't want to bother relearning any of it. I just run them all with track power and I am quite happy with it.

Most of my new locos have been Aristo and it was simple to put Revolutions and Dallee sound into them and easy to remember how to use the Revolution so I have done that with them.

That leaves some older Aristo and newer non-Aristo diesel locos without a PNP interface that do not have sound systems in them. I don't run or value these enough to want to put either Revolutions or new sound systems into them. 

It happens that I have a quantity of (long discontinued but new) MRC AD332 DCC Sound Decoders (8 amp) that I had started installing prior to the 1st Revolutions I bought but I quit installing them in favor of installing Revolutions instead.

The MRC AD332 sound decoders are not great but MRC closed them out at a great price and they are well worth what I paid for them.

It occurred to me that it might be possible to use the MRC decoders under straight analog power purely as sound units (diesel sound only - no bell or whistle).

I tried feeding DC power to the track input with a 8 ohm speaker connected but no sound comes out.

Since LGB locos with LGB or Massoth decoders still function (including sound) under analog power I thought it might be possible to achieve the sound function only from these MRC decoders.

Please DO NOT offer alternatives such as other decoders or other sound systems. I am NOT interested in buying anything - I have plenty of other alternatives if I choose to go that route. I am ONLY interested in finding out if it is possible to get sound out of these MRC decoders without a signal from a central station and if so how to do it.

If I have to I can do a full installation of the MRC decoders and I know that will work under MTS or DCC but i would really prefer to keep these locos running under analog track power.

Thanks,

Jerry


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## Cougar Rock Rail (Jan 2, 2008)

Hi Jerry, 

When I searched for that decoder it comes up as a N scale decoder with no mention of sound. In the case of the manual I found, it appears to default to NMRA standards for the CV's that control operation under DC power, so that's a good sign in that it might be possible to get yours to work. Is there anyway you can read the CV's and cut/paste in the values? It looks like CV29 and 12 might control DC operation. If it does comply I think you should be able to set what functions are active when running under DC. Here is what it said about CV29 (note Bit 2): 


Configuration Variable 29 Configurations Supported 

Bit 0 = Locomotive Direction: "0" = normal, "1" = reversed. This bit controls the locomotive's forward and backward direction in digital mode only. Directional sensitive functions, such as headlights (FL and FR), will also be reversed so that they line up with the locomotive's new forward direction. See RP-9.1.1 for more information. 

Bit 1 = FL location: "0" = bit 4 in Speed and Direction instructions control FL, "1" = bit 4 in function group one instruction controls FL. See RP-9.2.1 for more information. 

Bit 2 = Power Source Conversion: "0" = NMRA Digital Only, "1" = Power Source Conversion Enabled, See CV#12 for more information, 

Bit 3 = Bi-Directional Communications: "0" = Bi-Directional Communications disabled, "1" = Bi-Directional Communications enabled. See RP-9.3.2 for more information.` 

Bit 4 = Speed Table: "0" = speed table set by configuration variables #2,#5, and #6, "1" = Speed Table set by configuration variables #66-#95 

Bit 5 = "0" = one byte addressing, "1" = two byte addressing (also known as extended addressing) See RP 9.2.1 for more information. 

Bit 6 = Reserved for future use 

Bit 7 = Accessory Decoder: "0" = Multifunction Decoder, "1" = Accessory Decoder (see CV #541 for a description of assignments for bits 0-6) 

*Note If the decoder does not support a feature contained in this table, it shall not allow the corresponding bit to be set improperly (i.e. the bit should always contain its default value). 



Keith.


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## Dan Pierce (Jan 2, 2008)

The 8 amp sound decoder is the AD322, a typo by the poster??? 

Nothing in the manual shows DC compatibility. 

You may try cv 13 and 14 for functions to be active in DC mode (see NMRA standards) plus set CV29 to 4 for 14 speed steps(MTS) and analog operation. 

I do not believe that MRC adheres to NMRA standards completely, as CV13 and 14 are not listed in the manual on this decoder plus the 21 volt limit for voltage. 

I had 4 of these and swapped them out during warranty for the 1818 and 1819 versions which do operate in analog/dc. 

I still have the AD324's which are the non sound versions and DC is flaky, some work, some do not work on DC for the lights.


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## Greg Elmassian (Jan 3, 2008)

Yep, change bit 2 to be on is the standard way to allow DC operation. 

But the phrase "only" implies no DCC response, that is not possible. 

so setting CV 29 to 4 is the first thing to try. 

Greg


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## Jerrys-RR (Jun 21, 2010)

Hi Keith,

My mistake. I meant to say that they are AD322 decoders but I wrote AD332 decoders. 

http://1stclass.mylargescale.com/je...arison.pdf

G AD322 Diesel Directional plus Light Effects 36x88x23* Yes 2” 4 sound functions-F1 to F4 Discon.

Here are the instructions:

http://1stclass.mylargescale.com/je...ecoder.pdf

and Analog Enabling (which I do not understand) ...

http://1stclass.mylargescale.com/je...abling.pdf

*If I understand this correctly CV29 is defaulted to 2 and disables analog operation but I should be able to reset CV29 to 6 and get analog operation (I just found this info on one of my computers):*

*Analog Speed steps Direction When address is 1-127 When address is 128-9999
* disable 28 normal CV29=2 (default) CV29=34 (default)
disable 28 reverse CV29=3 CV29=35
disable 14 normal CV29=0 CV29=32
disable 14 reverse CV29=1 CV29=33
enable 28 normal CV29=6 CV29=38
enable 28 reverse CV29=7 CV29=39
enable 14 normal CV29=4 CV29=36
enable 14 reverse CV29=5 CV29=37
* 

CV #29 Table
*





and something I don't understand at all...

http://1stclass.mylargescale.com/je...CODERS.pdf

I have LGB and MRC central stations along with LGB and Massoth MTS and DCC remotes so I can program the decoders (once I figure out or remember how they work).

I notice that when I power the decoders with a MTS/DCC signal the relay clicks and the sound works which makes me wonder if I can just remove the relay cover and mechanically lock the relay(s) into the energized position (or remove the relay and jumper the circuit board wiring) to lock the decoder(s) into analog mode and see if the sound does not work under analog that way.

Of course if I can program the relays into analog mode and that works, my problem would be solved.

Thanks,

Jerry


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## Jerrys-RR (Jun 21, 2010)

I tried reprogramming CV29 to either 4 or 6 with a LGB 55015 Universal Remote but no luck. It may be that the AD322 is not capable of being set to DC operation or I may need a different way of programming the decoders.

Then too I may not be doing it right.

Jerry


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## Greg Elmassian (Jan 3, 2008)

I have some. You did not mention what address the loco is set to. (long or short address). 

Remember you can set a long address of 3, so the value of cv29 could be different. 

Also, some decoders won't work on analog in 14 step mode, and since you have an LGB controller, chances are pretty good that you could be on 14 ss. 

I'd do a decoder reset, then use the programming track and set cv29 and then read the value back to be sure you are doing what you think. 

Greg


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## Dan Pierce (Jan 2, 2008)

The relay is used for reversing motor direction, even the AD324 has a relay and this decoder does not have sound. 

And the sound has a LM7809 regulator which may make sound flaky at low speeds on analog layouts.


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## Jerrys-RR (Jun 21, 2010)

Posted By Dan Pierce on 10 Feb 2012 05:02 AM 
The relay is used for reversing motor direction, even the AD324 has a relay and this decoder does not have sound. 

And the sound has a LM7809 regulator which may make sound flaky at low speeds on analog layouts. 



Hi Dan,
 
You were right about the relay reversing direction. I have a couple AD322's I was going to throw away (I forget what was wrong with them) so I did not mind breaking into the relays and manually throwing them.
 
I was able to reprogram other CV's in the AD322's with the LGB Universal Remote so I am pretty sure that the AD322's are not capable of analog sound operation.
 
My primary plan for this was to put sound into a LGB See-Thru F7A & F7B that were given to me because they did not work (no motors in the A unit and the B unit sound system quit after a very short time).
 
I had previously converted this loco set to DCC for the owner with an AD322 and it had worked fine (DCC mode only) but when I was given the loco set I converted it back to analog track power, installed new motors, cleaned it up (it has thousands of hours of running time and was kept outside for years). I wanted a cheap sound system because I don't know what caused the original sound system to fail and I was unwilling to risk another LGB F7B sound system in it.
 
I will probably just put a couple LGB 4235 sound cards in the F7A & B.
 
Thanks,
 
Jerry


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## Jerrys-RR (Jun 21, 2010)

I've pretty much finished this project now. I gave up on getting the AD322 sound to work with track power and instead I have put LGB 4267 sound boards in both the LGB See-Thru F7A and F7B. Now the locos have sound (no bell or whistle) and my only out of pocket expense was the two motors for the F7A's.

While trying to come up with some sort of practical use for the See-Thru's I decided that, with all the flashing lights, they would look good as track cleaning locos pushing a track cleaning car with a trailing caboose. Its too bad LGB never made a See-Thru Caboose as that would have looked neat.

Jerry


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