Julian99

Thanks, I didn't know that! Maybe best not to try that again...... Yes, I'm positive. Good thought though :-) Oh that much variation? I suppose for £7.49 from screwfix I can't really complain. I think my original idea of measuring voltage drop as a way of checking for digital signal corruption is a complete waste of time. Yes, a few days back the command station successfully ran the same loco on the rolling road (I've only got one EM gauge DCC chipped loco). It also successfully ran a 'OO' DCC chipped loco on the rolling road. Today, the EM gauge loco wouldn't run on the rolling road, the 'OO' one would. So you are right, the command station is working. The EM loco or its decoder is the problem. So I've just spent the last hour or two tweaking the pickups to try and get the loco to run on the rolling road. With the body off I noticed a tiny spark on the circuit board. On closer inspection the red (track wire) is soldered to a blob oh so close to the blob for the grey motor wire. And the uninsulated end of the red wire is a bit longer than ideal, long enough to just touch the grey wire blob. Having nudged the red wire away from the grey wire blob I'd like to be able to report that it is all working. Sadly not. Right now: The loco chassis without body will run in both directions. Quite badly (stops abruptly, pauses for a second, then accelerates smoothly away). But that is probably due to me messing with the pickups. Rotate the chassis 180 degrees so the chimney faces West instead of East and the loco won't run at all, in either direction. Go figure that one! Put the body back on, and the loco won't run at all, no matter what direction the chimney is facing. I guess I need to resolder the red wire connection. On the plus side, the behaviour is consistent between the rolling road and the layout, so I feel like I'm making progress! There is a learning point here about being sure to use a loco you know to be a reliable runner when testing a layout..... Julian

Many thanks everyone for taking the time to reply. Much appreciated. There are no extra bits or other controllers attached to the the wiring. In fact I'm currently down to just one tag strip powering 5 pairs of droppers, with the DCC unit connected directly to the tag strip. With nothing else. And it still won't work. So checking the (much reduced) wiring: With DC power: Check with bulb --> bulb lights up Check with DC loco --> DC loco runs fine With DCC power: Short out the rails --> DCC command station cuts out Do continuity test, checking resistance across each connection with a multimeter --> resistance zero across each connection Do voltage check at different points following DigiTrax suggested method --> little or no voltage drop Run DC loco as '0000' -> loco runs fine Run DCC loco with analog bit on --> loco runs away Run DCC loco with analog bit off --> loco doesn't move This can't be a wiring fault at all. It has to be something else. Duff command station (unlikely)? Duff decoder (possibly)? Duff loco (most likely)? So a mate is going to lend me his Prodigy Advance to swap with the DigiTrax one, and I've ordered a new decoder (a zimo one this time) to swap the decoder. But I think it is the loco, so I need to get another DCC chipped EM gauge loco (I've only got one). This will take a while as I'll have to convert it to from OO gauge, and it takes a few weeks to get the wheels for the conversion. Julian

I assumed the same, but I'm having difficulty getting the command station to work. I'm building a new layout. So far I've built and wired just the loco depot part and it works fine under DC. Then I decided to convert it to DCC. The DCC 210+ works on my test track and powering the rolling road. It works if I patch it into a single tag strip to power half a dozen or so droppers. But it doesn't work if I wire it into the whole loco depot. By not work I mean the loco does a runner with the analog bit on, and sits there and looks at me with the analog bit off. The loco runs beautifully under DCC on the rolling road. So there is power to the track, but the DCC signal must be corrupt as the loco can't read it. I concluded my wiring is at fault so ripped it off the first baseboard to re-do it. So now I'm wondering how to check the wiring is good as I re-do it? For DC checking the wiring is simple, just use a multimeter or a light bulb to check for power after every connection. The bulb either lights up or it doesn't. But for DCC, checking for power won't check that the DCC signal is still good. So my plan is to check for voltage drops after each connection. Hence measure the voltage at the command station output terminals to get a baseline and then check it after every connection is made. The good / no good test being no more than 5% drop. I'm not convinced by this approach, so if you know of a better way to check DCC wiring as you do it, then let me know! Perhaps there is even a handy gadget for this? Julian

I got a reply from Digitrax: 'Your track voltage is fine. The Article needs to be updated with the new tolerances.' Naturally I asked what the new tolerances should be: 'I’m doing some testing and will be working with our engineering dept. for the new tolerances. It will most likely be .5 - .65v difference.' So I guess that means 0.53V difference is all fine and I should stop worrying about it?

Thanks Nigel Yes, going back to the retailer could be the answer. If there is something wrong I'd like to get it fixed before the warranty expires! I've raised a 'ticket' with Digitrax support, I'll wait a few days for their reply before calling the retailer. Thanks Julian

I recently purchased a DCS210+ command station and am in the process of connecting it to some newly built and wired track. The command station is powered by a PS615 power supply, and set for 'HO' track. At the weekend I checked the track voltage following the instructions in: https://www.digitrax.com/tsd/KB909/track-voltage-measurement-on-dcc-layouts-with-dire/ I measured the DC voltage with a digital multimeter on the 20V scale, between the 'GR' and 'RA' (Ground to Rail A) screw terminals and between the 'GR' and 'RB' (Ground to Rail B) screw terminals. I got the following results: GR to RA 7.04V GR to RB 7.57V Total 14.61V Difference between Rail A and Rail B = 0.53V Prior to these measurements I made sure that analog address 0000 was set to speed zero. KB909 above says each rail should measure between 7.2 and 7.8V, with a total between 14.4 and 15.6V. Also the difference between the rails should not exceed 0.2V (although will still work up to 0.5V) The Digitrax Big Book of DCC (p154) says 'The voltage between each rail and ground ... should not differ by more than about 0.4 volts'. Does this 0.53V difference between rails matter? Have I got a duff command station? Any advice welcome Thanks Julian