DCC Problem - The shunter that couldn't

[gavino200]

This is a problem with a non-Japanese loco. But it's also an issue about DCC decoders in general.

 

The situation. I bought a Micro trains Area 51 train around five or six years ago. It's cheesy but my son liked it and I thought it was cute. The loco is a MicroTrains SW 1500 diesel shunter. The set I bought was DCC. I had assumed it came that way from the factory, but it turns out to be an aftermarket install. 

 

https://www.trainz.com/products/microtrains-99321240-n-scale-area-51-train-set?variant=41427944198

 

The loco runs extremely slowly even on level track. It has always run very slowly. It runs faster, but still slowly in reverse. I've lubed it and cleaned it. And I replaced all the contacts (microtrains) use funny little whiskers that are a nightmare). I've sent it to MicroTrains but they wont touch it as it is DCC. I've heard from a number of people that this loco shouldn't be this slow. Most people think it much be a problem with the decoder.

 

Up until now I haven't been about to identify the decoder, so I haven't messed with it. Luckily I found it last night while browsing Digitrax decoders. It's a DN126m2 designed specifically for this loco. 

 

http://www.digitrax.com/products/mobile-decoders/dn126m2/

 

I added it to my JMRI roster as the correct decoder, and played around. But I really don't know what I'm doing. I set "max voltage" to the maximum allowed. No success. Also, the speed table is the standard straight line from 0 to max. 

 

What are some of the parameters in JMRI (or otherwise - direct programming with the handset) that may have some bearing on the speed of the loco.

 

I also have some other locos that I suspect are capable of going faster but may be hobbled by software settings. Nothing to this extent though.

[Kiha66]

Have you done a decoder factory reset (should be cv8 to 8 for digitrax)?  I've found that sometimes can help with these.  Also try running the loco on DC to see what the top speed is.  The decoder should sense the DC and let the train run in basically bypass mode, so you can see if the locomotive is slow in DC as well.  If it is then its a mechanical problem, if not its very likely the decoder.

 

Good luck!  I've had a friends bachmann SD45 sitting on my workbench for months now and it has the same problem with the factory decoder.  On DC it zips right along while in DCC mode it can barely reach 30 scale mph.  No idea whats causing it as bachmann says the decoder is fine, I'm about ready to bypass the motor and have it be an unpowered unit.

[gavino200]

8 minutes ago, Kiha66 said:

Have you done a decoder factory reset (should be cv8 to 8 for digitrax)?  I've found that sometimes can help with these.  Also try running the loco on DC to see what the top speed is.  The decoder should sense the DC and let the train run in basically bypass mode, so you can see if the locomotive is slow in DC as well.  If it is then its a mechanical problem, if not its very likely the decoder.

 

Good luck!  I've had a friends bachmann SD45 sitting on my workbench for months now and it has the same problem with the factory decoder.  On DC it zips right along while in DCC mode it can barely reach 30 scale mph.  No idea whats causing it as bachmann says the decoder is fine, I'm about ready to bypass the motor and have it be an unpowered unit.

 

Thanks! I'll try both of these ideas. 

 

The other loco that runs very slow is a Bachmann J-Class. Not nearly as bad as this one. It's passable, but a whole lot slower than a Kato steamer. It think I'll take a look at it next if I have any luck with this one.