This is a problem that I have had for the last couple of years and finally gave up on. I purchased Soundtraxx PNP Sount decoders for 3 LIfelike GP9's about 2 or 3 years ago and retrofitted them into my GP9's that had DIgitrax DH163P decoders. They havve never worked without stopping every couple of feet. I went through the track cleaning, checking isolation from frames, gear meshing, and any other thing I could think of. They have been on the shelf since that time. I thought that I had a bad decoder but find it unbelievable that all three could be bad. I have been using my digitrax decoders during this time with no problems except I have no sound. My control system is Digitrax Super EMpire builder system with jumpers every 4 to five feet. The stalling happens at randoms locations. HELP!
Do you mean that the locomotives stop every couple of feet, or just the sound? If it's just the sound, I had a similar problem with a Kato HO scale snoot nose (SD-40?) until I read one of the tips on Tony's Train Exchange's web site which indicated that Kato had changed their electrical pickup scheme on my particular model, and it had proven to be very problematic. I soldered electrical pickup wires directly to the truck frames instead of relying on Kato's flakey wipers, and the problem was solved.
The flywheels in the engines you have keep them running smoothly enough for the Digitrax motor control decoder to function correctly, but the slightest interruption in electrical current to the SoundTraxx decoders causes them to cut off and then restart. Adding a capacitor to the SoundTraxx electrical pickup wires, either red or black, may solve part of this problem, but I would very carefully examine the pickup wipers on the locomotive trucks for intermittent breaks in contact. The power dropouts may be only microseconds in length, but that is still enough to raise havoc with a SoundTraxx decoder.
If you send an e-mail to SoundTraxx explaining the problem, they may be able to suggest a fix. I have never had to contact them, but have heard that they are very responsive.
Maybe it does not apply but you might look into this if you are soldering inclined.
http://www.soundtraxx.com/documents/technotes/dcc/dsxcap_upgrade.pdf
Here is another link.
http://www.members.optusnet.com.au/nswmn/dcc_articles.htm
Scroll down. On the right you will see "stay alive" plus a lot of other good DCC info.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Some time ago MR had an article about wiring a second decoder to a sound decoder with the sound decoders drive control disabled. Any body remember what issue this was?
Thanks for the reply. I meant the engines stopped. Sound is okay. I am going to try the "add capacitor" plan now. I have nothing to lose because they don't work now.
The only issue I've had with Soundtraxx decoders is they're very touchy about dirty track and wheels. BTW since you didn't mention wheels, I would make sure those are clean also. I had a devil of a time getting an engine to run after a sound installation, kept stalling out. I cleaned the track but still had trouble. Finally checked the wheels, turned out during the installation a little soldering flux had gotten onto one wheel, and it was causing the engine to lose connection to the track. Once the wheels were thoroughly cleaned, it ran fine.
Otherwise, I would try putting the sound decoder in another engine, say an Atlas one. If it works fine there, the problem is the LL engine, not the decoder.
73
Bruce in the Peg