Last night I finally said RIP to my QSI sound decoder in my N scale Walthers 2-8-8-2. Something shorted out in the tender and now its dead on the track with no response. I began to hear a click/flickering sound the second it started. My Digitrax Zephyr and Sprog programmer tap out the second I apply power with short circuit prompts. Needless to say, this was a decoder from 2008 when factory installed in this locomotive. 17 years ain't bad, right? My NCE decoder in my N FM Trainmaster from Atlas also went wonky. It no longer holds it's speed settings consistently (it does whatever it wants now) and won't move anymore until I apply 50% throttle. I've spent an hour changing v-start/mid/high and even tried speed table to no avail. I'm writing it off as French toasted. This was a decoder from a 2016 production run installed at factory. So only 8-ish years. So I guess with my recent experience, what has been everyone else's experience? What can we expect for lifetime of electronics? I'm only speaking from the N scale side but anyone from any scale is welcome to give .02 cents. I love DCC but do not look forward to the increased cost over time to replace components. It isn't something you think about first hand when buying a new locomotive.
For the NCE decoder, did you try doing a factory reset? I've heard of decoders losing their minds but a factory reset usually restore them. I've never heard of a decoder dying due to age or non-usage. I can't say that I have experienced any of this myself and I have decoders that I installed over 15 years ago, some I don't run often, and they have not given me any problems. Don't even need to do a factory reset. Knock on wood!
There are no moving parts to "wear out", so in theory they should last forever, but that rarely happens........but predicting lifespans is almost impossible. There are so many components involved and any one of them could take out the board if they go bad. But most of my board failures have been during install, due to to derailments/short circuits, ect. I don't think I've ever had one die of old age. Same for consumer electronics......they usually die due to the failure of motors, switches,ect. and not due to the electronics.
I got into DCC in 2013, so my oldest decoders are some 12 years old. Most are Digitrax, because at the time they were the most affordable and widely-available decoders. They all still run, but I've noticed that the speed table settings for some of them have to constantly be re-programmed. So I don't know if there's a RAM issue with those decoders or what. These days I use ESU LokSound decoders due to their robust programming options. I wish they had LokPilot equivalent decoders for all of them though.
Well, I have a few decoders that are over 25 years old now. They are from before they used higher "silent drive" PWM frequencies and emit an audible buzz when running, so they aren't run as frequently as most other locos, but I do run them and they still run as good as when new. I keep thinking I'll replace them because of the buzz, but since they do run fine there is always something higher on the priority list.
I've got a few QSI decoders that are ~20yrs old now, most are still working and were factory installed. I'd expect most of the DCC decoders to last for a very long time unless a short circuit results in physical damage to components on the decoder. It's also very possible decoders can be damaged with over voltage scenarios, mostly in keep-alive circuits which is a bit like the wild west as there are no common standards that manufacturers follow. I'd be interested in seeing some photos of the "dead" decoders to see if it possibly has visual clues as to what failed on them. In the case of your QSI decoder, I'd double check the keep-alive capacitors as it's totally possible they are causing a dead short across the connections. This can usually be tested with a multimeter to measure the capacity to see if it is within tolerances.
I have a number of Digitrax DN144K motor decoders in Kato Dash 9's. They're pretty basic, motor control with no BEMF, but they're still soldiering on. I haven't bought Digitrax in years, having switched to TCS and ESU. I see on the Digitrax archive that the DN144K was discontinued in 2003, so they've been running for at least that long.
I wonder how ESD (Electro-Static Discharge) susceptible/resistant some decoders are? Also, running N scale decoders on 15V DCC power supplies may be a little harsh. Unlike DC, where the tracks, and the loco motor never see the power supply voltage unless you throw the throttle wide open, the DCC waveform voltage is typically only a volt or so less than the supply voltage, regardless of the throttle position. That waveform is rectified (a couple of diode drops) and regulated to create the supply voltage for the decoder electronics, but not typically the motor's PWM waveform. Motors and motor driver circuits are generally pretty tough, but digital electronics and capacitors, not so much. Lose a power supply capacitor, and the decoder operation (including programming) could get pretty erratic.
Solid state electronic circuitry (transistors & microchips etc) should last almost forever, unless something gets burned out by over-voltage or a short-circuit. However, older electrolytic capacitors can die after a few years, and (if accessible and diagnosable) they can be replaced.
Electrolytic capacitors often fail after being un-powered for extended periods. Periodic or continuous power application tends to mitigate these failures (literally burn tiny internal shorts out as they form, before they become too big.) Solution: Run your electronics periodically. "Honey, I'm not playing with my trains; I'm performing periodic maintenance!"
I think it's a legitimate concern, especially if you go through all the work to convert loco's only to have the company discontinue the DCC unit and change the plug. My thought was if the plug stays the same, at least you can swap the module, re-program, and carry on.
Hadn't thought of/about it like that, but you have a great point! Wire in a standard socket, then you can plug in a replacement if/when needed, or you just want to try a different one out (different motor control algorithms, sounds, etc.) Standard sockets give you a lot more options than light-board-replacements do.
I've mostly seen the electrolytic caps go bad after 10 or more years, usually they end up holding no capacity or are a dead short. This is more common on capacitors from the 80s-90s though.
I am not an expert on the subject but can share that I had something like 14 of 15 locos which were in storage for 10 years or more and the decoders worked fine. Most are Digitrax plus one NCE and TCS equipped. My NCE Powercab bought in 04 that is rarely used still works fine everytime I use it. I run Digitrax these days and use it for programming if needed.
