I have had two DSD LC sound decoders fail by losing the volume of the amplifier. The sound is now almost inaudible, regardless of resetting the CVs.
I had this happen before and I thought it was because of the capacitor shorting out against the frame in that case (my bad taping job). But that one I sent in for repairs and it came back the same. I don't know if I should bother to cut out this latest one hardwired in and send it back too, or just use if for the motion and lights.
I have about four of them. I have been using 16 ohm transducers for speakers and so far, no problems. (Yea, I know they say use an 8 ohm speaker, but as an electronics tech, 16 ohms is less of a load on the amp.)
Did you send the speaker with it? Did they say they found someting wrong or not? Since you sent one back and you say it came back the same, have you tried a different speaker? This is the first thing I would suspect. The factory test bench will usually have a standard speaker that they use for their testing to check things out.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
gandydancer19 wrote: Did you send the speaker with it? Did they say they found someting wrong or not? Since you sent one back and you say it came back the same, have you tried a different speaker? This is the first thing I would suspect. The factory test bench will usually have a standard speaker that they use for their testing to check things out.
Well, I don't know about the speaker issue, guys. I have about 8 or 9 other Sountraxx of various types running well with similar speakers.
What gets me is that this latest one died on the shelf. The LC worked fine for the weeks I used it after installing. Then when taking it off the shelf again a few weeks later, Kaput!!!
Anyway, I copied the original post over to Jarrett at Soundtraxx and I just have to wait to see what his thoughts are.
Hmmm, I suppose its possible the capacitors are crappy, or a from a bad batch....but they are such simple devices, what could go wrong. I am more inclined to think the little sound amplifiers are a little dicey.
Any electronic component could fail or change value. Subsituting the cap is another simple thing to check. I have seen electrolytic caps short out and take out the main power supply rectifier diodes. If the cap is shorted, it will allow DC voltage to be present on the speaker. If this happens, it may blow the speaker or just cause it to be deflected one way and thus reduce the sound output.
As someone who has some experience with ESD, I would not think of it as an issue. Most components are less affected once they are in a circuit. ESD damage happens more often to the components before they are soldered in a circuit. Now that doesn't mean that ESD is not the culprit, but I would suspect it less because the unit was sent back, tested, aparently found to be OK or fixed, yet the problem remains.
I also want to add you might want to check the capacitor; I found an open cap packaged with one of the Soundtraxx LC decoders (I am also an electronics tech and have an capacitor checker).
BTW for the record, checking the speaker's DC resistance is not a good way to judge the impedance rating; in some cases they are close, but not always. The rating in Ohms is based on the opposition of current of the speaker at a nominal frequency value, usually measured at 1KHz (middle of the frequency response of human hearing). Also, the factory supplied coupling capacitor, placed in series with the speaker will help to limit low frequency current; if your speaker was 20 percent off in value, it will not hurt the amplifier.
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!