# DIGITRAX SDH166D Sound In One nothing but trouble in Atlas locomotive



## tkruger (Jan 18, 2009)

I purchased a DIGITRAX SDH166D Sount In One decoder to upgrade an older Atlas GP 38-2 that I have. Prior to the upgrade I measured the draw at DC full throttle and stall of the motor and it was well within spec for this decoder. Then fully cleaned and lubed the engine including the comm on the motor. After the install the are several intermittent issues:

1. If last motion was to reverse prior to stopping at some random time the locomotive may take off without any other sound, light etc in revers at high speed.
2. Horn and / or bell stops working other sounds continue, to get the sounds back power needs to be cut to the engine by turning the track it is on off then on. 
3. Sound occasionally makes a 'click click' noise similar to an old school amp popping.
4. Sound volume cuts in half after being idle for more than 30 seconds, must bring throttle up to get volume back.
5. Delay of at least a half second to any command I send.

I am using an NCE Power Cab. Is it possible that it just does not play well with this decoder? Other non-sound Digitrax decoders seem to work fine as do the NCE and MRC ones I gave used.


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## DonR (Oct 18, 2012)

The first suggestion when you have odd decoder actions is
to try a reset to default #3 and start over.

If that doesn't work, I know from experience, that you can
get help from Digitrax itself thru their web site. They
want you to describe the problem in detail and what
it is installed on. They likely will get back to you same
or next day. They'll replace it free if it's defective even
if you damaged it.

But some of our DCC gurus might come up with a suggestion
before you know it.

Don


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## Cycleops (Dec 6, 2014)

Did you ever get to the bottom of this one? Sounds to me like a defective decoder but I'd love to know how you resolved it.


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## tkruger (Jan 18, 2009)

Cycleops said:


> Did you ever get to the bottom of this one? Sounds to me like a defective decoder but I'd love to know how you resolved it.


Yes, sorry for the slow response. I wanted to get all the facts first. I reset everything and all those tricks with no luck. So I emailed DigiTrax just cutting and pasting the same information from my initial post to them. A day later they replied that this is a defective decoder and return it to them for a replacement. This I did. I had to pay postage to them but they paid to ship it back to me. I received a new decoder of the same model.

Now that was the good news, I am happy with the customer service.

Now for the decoder performance, note that I new this was a budget decoder at a rock bottom price so I was not expecting allot.

The motor control is not that great. The $12 NCE motor only that I used temporarily has better control than this. The sound is there but not great, it is only 8 bit. The real down side to the sound is that it can only play the engine noise and one other sound at a time. I.E. cannot play the bell and horn together. A random running noise kills the bell or horn if they are blowing. 

I was hoping that this would match the cheep combo that I have been using with great success in a smaller package. I have had good luck running the NCE $12 motor only decoder and the MRC Sounder sound only decoder together. As long as a decent speaker is used the sound from the Sounder is clear and crisp. It is not quite that of a Tsunami but for converted old locos it is close. The steam one is very close to that of my Athearn Genesis Challenger.

I will say that the MRC ones with the sound and motor controller in one unit somehow have worse sound than that of the sound only decoders. I would have thought that the circuits would have been reused but I guess not. These are no better than the cheep DigiTrax unit.

I guess your have to sacrifice something for cost is what I have learned. The two combo units were disappointing. Each sacrificed functional qualities for price and size. Two inexpensive single purpose decoders working together provided a good sounding and running combination that required space (that is often not there). And then the good one unit option cost several dollars more.

Sorry to get off track on this.


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## Cycleops (Dec 6, 2014)

That's very interesting, not off track at all. Providers us with an insight into what to expect from those all-in-one budget sound decoders.


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## tkruger (Jan 18, 2009)

Cycleops said:


> That's very interesting, not off track at all. Providers us with an insight into what to expect from those all-in-one budget sound decoders.


I am converting old locos so I cannot justify a $100 decoder for most of them. 

I tried the MRC Sounder and a NCE $12 decoder in an Manua 2-8-2 Camel Back and a Riverossi Cab Forward. The space was there in these even though I had to use a sugar cube speaker. To be hones these worked great. I did the same for an Riverossi GG1 but use MRC's electric sounder, once again great success and so on with two Athearn Blue Box F units. 

Then the $25 MRC all in one was tried. It just cuts every corner. I have four of these. They were all delegated to locos that see the track once in a while. Worst part is that they do not come with a speaker like the sounder did. Adding the price of the speaker the only advantage is the smaller space, would rather have no sound at that point and better control.


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