Having trouble with a decoder.

[froggy]

I have Kato SD40-2 and it takes a MRC decoder with sound and when I installed it I got sound for a second and then it went away.It is a drop in decoder.How do you reset a decoder?Might have to send it in to MRC.

[cacole]

If you have been on these forums any time at all, you should realize by now that MRC decoders are notorious for high failure rates.  The factory in China seems to have no quality control procedures at all.

Unfortunately, with N scale you have no other choice unless you have the proper tools and know how to solder.

[Hamltnblue]

Is the loco N scale?

It doesn't matter with MRC since they're junk either way but the replacement options depend on the scale.

[froggy]

You are so right about MRC.I should hadf done my homework first to see what decoder my loco would take before I bought it.Oh well, I have lots to sell.

[froggy]

Yes my layout is in N scale.

[rrinker]

 Some MRC decoders will reset to factory defaults if you set CV125 to 1

What sort of problem is it having? N scale drop-in decoders are notorious for havng contact issues, either with the frame halves to get power TO the decoder, or witht he motor tabs getting power to the motor - if it's the motor tabs you should have sound but it won't move. You also must be sure to carefully follow the instructions when installing to make sure the neither motor tab can accidently touch the frame, which will pretty much instantly fry the motor drive on the decoder.

                     --Randy

 

[froggy]

Talking about CVs, Can someone explain to me how to get into cvs when the loco is already programed? I have a NCE Power Cab.I have a loco that you can barely hear the sound and one that used to have all the sound but only now has a horn.

[fwright]

Here is a quote from MRC to somebody else who was unhappy with their MRC decoder install in a Kato SD70:

MRC Response
From: Frank V
To: DWIGHT SEDGWICK
Subject: Re: MRC Decoder with sound

due to the speaker size needed for n scale the volume is not going to be that loud
normally you should be able to hear the prime mover up to almost 1 foot away...the bell and horn up to 2 feet..this also depends on gear train/mechanism noise from the loco and how quiet the room is.
if you need more volume you can use a bigger 8 ohm speaker if you can find room for it inside the loco
we can not supply a huge speaker with the decoder, because it needs to be made so everyone can install it without any major modifications to the loco

Some of the implications are:

• if the sound is working but weak, the speaker install is the problem, not the decoder
• the very tiny speaker supplied by MRC is inadequate, especially if there is no airtight enclosure on the back side.  You need to install the biggest 8 ohm speaker you can with an enclosure. 
• to know if your decoder is working correctly - and to tune it - you have to be able to write CV values at a minimum.  The easiest way to take care of the CVs is with the NCE USB computer interface and Decoder Pro on a computer.  Otherwise, you have to pore through the decoder manual and read/write values for individual CVs - and they differ from decoder to decoder.

 As others have said, MRC decoders have a reputation for being short-lived.  Whether the MRC decoder quality has improved in the last year or two is an interesting question.  I know MRC is pushing their sound decoder setup in N, but even the HO guys will tell you getting decent sound out of a locomotive is rarely a plug and play event unless the decoder and speaker are pre-installed.  Even a manufacturer's installation is not always a guarantee of satisfaction.   Things are that much worse in N with much more limited space for a good speaker and enclosure.

my thoughts, your choices

Fred W