Digitrax DZ125: Much luck?

[CaptOblivious]

I've just not had luck with the DZ125. Every last one I've ever installed has failed, and more often sooner rather than later. The last one ran fine for about 60 seconds before failing—no burn marks or release of magic smoke, but it causes a short circuit whenever I put it on the tracks. Indeed, I've probably killed a dozen of 'em, and most for no clear reason whatsoever. I've also killed a number of TCS CN-GPs and TCS Z2s—but TCS tech support tells me that these two models are rather fragile, and prone to early death in the wrong hands. On the other hand, I've never had any malfunctions from: Digitrax DN143 or DN163K0a, TCS M1 or FL4 (which TCS tech support tells me are nearly bullet-proof), any of Kato's (except the one that I dropped on live rails by accident!), and NCE Z14SRP (which has a reputation for being bullet-proof too).

 

So, is the DZ125 a fragile decoder? Or am I just unlucky?

[CaptOblivious]

Anyone else have an opinion? The poll results are thus far inconclusive…

[Bernard]

Off hand I can't remember the decoder the DZ125 replaced, I think it was the DZ123?

But as a replacement, I haven't been that impressed. I've already blown 2 decoders and have one train that I've taken apart 5 times now and it just isn't responding to that decoder. I have an older Lenz decoder that I'll probably try next.

[KenS]

I don't think it replaced the 123, Digitrax still lists both: DZ123 for $19.99, DZ125 for $24.99.  The DZ125 adds BEMF and support for 20V DCC systems (the DZ123 is limited to 18V).  However, the DZ123 supports 2.0 Amp current for a brief time, while the DZ125 only supports 1.25 Amps (both are rated for 1.0 Amp continuous and 0.5 Amp total for the function outputs).  That shouldn't matter in any modern N-scale loco, as stall current should be around 0.3 Amps, but it does suggest there's a bit less headroom in the design.

 

Oddly, the DZ123 is listed as FCC Part B compliant, while the DZ125 is not.

 

I've never installed either (yet), although I have several of each on the bench waiting to be installed when I get around to working on my "needs soldering" trains (I picked up the DZ123s cheap at a LHS clearance sale).  I've been playing with a DZ123 connected to an ESU decoder tester (which uses an HO-sized motor) for a bunch of decoder-programming testing, with no problems.

[KenS]

Two years on from the above post, and I'm finally starting to work on wire-in decoders, and I want to revisit the original question posed by this thread: what experiences have people had with the DZ125, and has anyone had problems that DIDN'T involve a Tomix train?

 

Don's mentioned his problems, and I recall Growly the DE10 eating DZ125s as well. But googling about, the decoder doesn't seem to have had too many issues, although I ran across one posting alleging (with no supporting info) that the initial batch (in 2008) had been bad, but Digitrax fixed "the problem" on subsequent batches.  All of the other problem reports I've seen were on this board, and Tomix seems to be the common factor. Most online comments about it were quite positive, and on paper it looks like a good choice for my EMU motor decoder.

 

So, anyone have DZ125 problems not reported yet?  Did they involve Tomix or not?

 

BTW, while digging for this info, I turned up someone who'd figured out how to install a supercap to a DZ125 for power protection.  His instructions aren't too detailed (I'd think you want a resistor in there to limit inrush, for example), and the video (below) doesn't show anything beyond a running train.  But if true, it sounds like an advantage for the DZ125 that has me thinking about them even more (I was already inclined in that direction, but I am planning to test several decoders before I commit on a large scale).

 

[Martijn Meerts]

I don't have any experience with Digitrax, but I've been pretty active in the thread about Tomix supposedly eating decoders. As said in that thread, I've not found any reason whatsoever for Tomix to give issues with decoders where other brands do not. Tomix doesn't have any special circuitry, nor do they have special motors (I've taken a few motors apart to check it first hand) By now I've installed several different brands of decoders in a variety of Tomix trains, and really only 1 decoder has shown some issues, but then again, I have that same decoder in a Kato train, which is also showing issues. Those are 6 year old decoders though :)

 

That said, there's a good chance the initial batch had a bad component or bug in the firmware. And there's a good chance the new batches (with probably better components and updated firmware) work just fine. If they're not that expensive I'd just go ahead and order one and test.

 

For me, decoder choice is mainly based on size, running characteristics and to a certain degree features. I've been using Lenz Silver+ mini for a while now, which have 3 pads to solder a 'power pack' on, (capacitor with some extra electronics.) The capacitor is too big to fit in most models, and would really only fit in some of the MU's, but would be hard to hide. I do have some 0-scale Lenz locomotives which come with such a power pack pre-installed, and it actually works really well. The 0-scale locomotives can runs several seconds with lights and sound on without getting track power at all.

 

There are other brands offering capacitors as well, and the decoders they work with usually have specific pads on them, so they're easy to solder. You don't have to go soldering them onto the tiny, easy to fry SMD components on the decoder itself :)

[inobu]

The problem is most likely heat soak during the soldering process either in manufacturing or installation.

 

I had 2 out of 7 bad. One from heat soak (Me) and the other DOA. I think the PCB soldering looks sub par on the DZ123 but things are cheap for a reason.

 

 

 

It is all about quality control and you get what you pay for.

[keitaro]

I have heard many times the 125 is more sensitive to power being pulled and that the tomix motors are greedy.

 

This may have been the case for don's older de10 2 years ago. But the new models from tomix need much less power than kato recent models to get going on my dc controller.

 

One would think this would be the same for dcc.

 

Still I have heard the 123 didn't have these issues with the motor from older tomix so i guess it's either getting too much power or bad workmanship on the chip.

 

I wonder though if it was poor quality manufacturing surely 2 years on this would have been addressed?

 

Either way my testing with my newly acquired digitrax xtra and the 123z and 125z I have not had issues with the few i have tested.

 

Also i did do a terrible job on soldering them in to the point I figured I had likely burnt the motor from taking too long. I haven’t done the lighting though in the 3 models I have done so far.

[Ochanomizu]

I have installed seven decoders.  All were DZ125.  I have not had any failure yet.  Maybe it was a particular batch of decoders.

 

Digitrax has a "no questions asked" warranty.  They will replace all faulty product within 12 months.  You must pay your own shipping though.

 

If there was a fault in an early batch I would imagine that it has now been rectified.

[keitaro]

thats what i had figured.

 

I'm going to buy a few more of these for my green max kit models that don't have lighting in them (front and rear)

 

Would i just be wiring the + wire to the + side and the - to the - sides on both the motors there mounted in opposite direction so i might need to criss cross them?

 

either way if it's a power drawing issue it should happen running 2 motors surely?

[Guest Closed Account 1]

I had a DZ125 in my Kato Kobo Mikado steamer. Didn't last long. Changed it to a TCS M1.

 

TCS doesn't make you pay return shipping.

 

TCS Techs don't regurgitate the same printed decoder manual you the consumer have.

 

They'll help you figure out your individual need for CV combinations.

[keitaro]

i have had really good info come back from digitrax so far maybe you asked wrong..

 

Either way i'm yet to have any issue for this decoder we shall see i guess with my next lot.

[Guest Closed Account 1]

i have had really good info come back from digitrax so far maybe you asked wrong..

 

Hmm no. It wouldn't communicate with any dcc controller a couple years back at a show. Other members called Dogitrax to speak with a specific person and he couldn't help.

[Spaceman Spiff]

Bringing up an old thread. I have stopped buying DZ125IN decoders. Too many issues not working with European sets and lately I seem to sending a few back for warranty. I have had to return some ESU's also. :-(.

I haven't had any issues with the TSC EUN651's so I think I will stick with them exclusively now.

 

I think Digitrax is tryting to cut costs with decoders and it's affecting their reliability. I am also not happy how they are going to the one size fits all for their drop in line for loco's such as the Kato 4400, SD40 etc. They don't fit as well as they used to and some installs now require shell mods to fit properly.

 

 

 

 

 

 

Spiff

[Vato]

I have installed on the kato stuff (4) almost 1 year and no fails

Edited January 18, 2014 by vatato

[dottney]

I use these and other Digitrax z & n decoders in many n scale applications. I actually prefer NCE decoders but for simple applications you can't beat the price of the Digitrax decoders.

Dave

[Melandir]

I only have Kato decoders manufactured by digitrax, and at the moment they are working fine

for all the other models I prefer to go with TCS M1 and FL4 and K0D8 due to Railcom and no fail there

[E6系]

Hello,

 

I just thought I would mention that DZ125 has been replaced by DZ126.

[mbloes]

Interesting topic as I thought I had this problem, which I just attributed to the DZ125 being a low-cost decoder.  However, when this particular train fried four (!) decoders in quick succession, I decided to investigate further.

 

This particular train is a Greenmax 103 series with two motors - one each for driving each bogie:

 

 

The short answer is, after much isolating and narrowing down, one of the motors was shorting from a dirty commutator on the armature.  It would work fine with medium voltage applied but when the voltage was lowered it would short and stall (and then fry the decoder).

 

Being a veteran slot car guy, disassembling and servicing cheap Japanese electric hobby motors posed absolutely no problem.  I removed the armature and cleaned the comm (white arrow in the photo below) and brushes, reassembled it and everything was back to where it should be.

 

 

I don't know much about decoder design, but you would think there would be some type of protective circuitry, but there you go.

Edited June 18, 2014 by mbloes

[kvp]

Decoders either use a dedicated H bridge chip, usually with protection or they use simple transistors, usually without protection. Also some decoders use feedback for motor regulation, which only works with single motors. The transistor version is usually cheaper and can be made smaller for the same current capacity, but they lack protection.

 

Ps: You have a good eye that you discovered the commutator short, it's very hard to detect...

[mbloes]

Great info kvp.  So then, I'm wondering which brand of decoder would be most compatible with these two-motor configurations.  I was just going with a minimal type of decoder as I'm not using it for any functions other than motor control, but obviously there is more to it than that.

Edited June 18, 2014 by mbloes

[Edw]

I have 9 locos I run nearly daily. 6 of these have DigiTrax decoders (of which 3 are DZ size), and 3 have NCE decoders.

 

The DZs are in 3 switchers: Walthers 400 HP diesel; Model Power 0-4-0T; and Bachmann 44 ton. They all work great. I think the key may be the right soldering approach- enough heat to melt and make a good solder joint and then immediately take the heat from the joint. Of course, the track work needs to be great for the short switchers to work well, and I did a lot of joint soldering and frog powering to enable crawling through switches.

 

I have burned out NCE and DigiTrax decoders, but I think circuit problems in the locos were the reason.