Crosland

If that's really what you were told, then they are not knowledgeable. No DCC decoder can be programmed at 1 V. What they probably meant was that there is only a very low current available for programming and the very high inrush current to charge the stay-alive triggers an overload detection. This can also be an issue when trying to turn the power on for a layout with many stay-alive fitted locos. Better decoder/stay-alive combos will limit the charging current.

I have found the collection service to be utterly reliable. It's brilliant, in fact, and a much better experience than the rude counter staff in the village PO. The only times I have had issues, including chasing the postman down the street to ask why he didn't collect, turned out to be my errors.

I've never seen it. I would use individual wires and twist them if you just want to keep them together.

LEDs don't suddenly "come alive". All that example shows is a Vf of 1.9 V at 5 mA. You need to look at the luminous intensity v. forward current graph in the data sheet, which you will see is pretty much a straight line, no sudden turning on on coming alive. A modern high efficiency LED will light at less than 5 mA but, as you can see, you can see you are well down the curve and the Vf will not decrease very much in your example. In the other direction, if you try to control the voltage, you can see a small change in voltage (0.1 V) leads to a near tripling of the LED current. Voltage control of LEDs is too imprecise, which is why they should always be current controlled. A LED operating normally at 1.5 V is a physical impossibility, unless someone has discovered new materials and rushed them into production without telling anyone. They would probably be in line for a Nobel prize in physics.

Sorry, but you are showing your lack of understanding of LEDs again. LEDs are diodes, they behave much like diodes but are somewhat more fragile, e.g., very low reverse breakdown voltage. There is no "turn-on" voltage at which they suddenly start working. LEDs are, in any case, current driven. That's why you use a resistor to control the current. The technology has not changed and typical Vfs have not changed. If your LEDs work on a single AA battery then there is some other electronics involved, to boost the voltage. ALL common LEDs will go pop on 9V, and always have done. Any that don't have built in current limiting. You will often see these sold as, e.g., "12 V LEDs". The only reason you get away with running a LED from a coin cell with no resistor (as you have stated in the past) is the high internal resistance of the cell acting as the current limit.

If it persists, contact us directly to discuss, but I will be away for a few days so you may not get a response straight away. Andrew Crosland sprog-dcc.co.uk

What readings you get will depend on how you connect the meter. If you measure on DC from one track to the booster "ground" or 0V then you will probably see half the voltage as the DMM will average the square wave that is switching between 0 and +V. See https://www.digitrax.com/tsd/KB909/track-voltage-measurement-on-dcc-layouts-with-dire/ for more details. If you measure across the rails then you need to set the meter to AC and, as someone said, it can be a bit of a crapshoot. There is, somewhere, a web page by someone who tested a lot of DMMs for measuring DCC, but I can't find it at the moment.

That's interesting, thank you!

If they program fine then there should be nothing to worry about. Does "programming" include both reading and writing? Traditionally the ACK pulse was generated by pulsing the motor, often resulting in audible feedback and the loco creeping along the programming track. The effect depends upon the motor, as well as the decoder. It's also possible to simply switch a resistor or other load across the tracks to generate the ACK. This would not result in any noise or movement.

Sorry to resurrect an old thread, but I have some insight and wanted to ask if your problem was ever solved? Whilst working on a new booster design I was investigating "soft start" options and realised that no one mentioned the effect of layout wiring, or I missed it if they did. At one, impossible, extreme, zero resistance between the booster and the discharged capacitors in the decoders, and a limitless PSU would result in an infinite current spike but the capacitors would charge very quickly. In the real world, the peak current is determined from the track voltage and the wiring resistance, by ohms law, at time 0. The current decays quickly, and exponentially, as the capacitors charge. The aim is for the current to decay to a "safe" value before the booster (or other device) trips. A higher resistance between the booster and the locos will limit the current and flatten the curve, possibly resulting in too high a current flowing at the trip time. This is just another reason to employ hefty (low resistance) bus wiring. As an example, 15V track voltage, 0.2 ohm wiring into 20,000 uF will result in 6 A flowing after 10 ms. I used a very short delay as switch mode PSUs can cutout very quickly if overloaded. The reason some systems cut out very quickly is to prevent the PSU cutting out. The Tam Valley TurnOn Module switches a 0.5 ohm resistor into circuit at startup. After the same 10 ms the current will be almost double, at 11 A. Possibly still enough to trip the booster. Indeed, the OP reports that this module did not solve his issue. Examples calculated using https://calculator.academy/capacitor-charge-current-calculator/ An interesting test would be to power up with all of the locos at the farthest point from the booster (maximum effect from wiring), and again will all locos as close as possible to the booster. Technical bit: A more robust booster design would be to employ a current limit, not a trip. That, however, requires a lot of heatsinking, and very careful thermal design, as the limiter will probably be a MOSFET operating in it's linear region.

You've got them the wrong wat around. Service mode needs a programming track and the loco is put into service mode to tread or write. POM is Program on the Main, also known as ops mode, works anywhere on the layout, but is write only unless you have something like Railcom.

Yes, but you might need to change a setting in the 'phone (at least if it's Android) to connect to a network with no internet. You need a wireless access point or router. Be sure to change the network name (SSID) and admin password away from the defaults. The individual items should have instructions on how to connect them. These days it can be as easy as pressing a button or two and everything is setup automagically.

And the prize goes to...😀 A very easy way to measure the track voltage is to simply rectify it and add a bit for the diode losses. Maybe add a small smoothing capacitor. The DC voltage you measure will be the RMS, which is the same as the peak. True RMS meters will work, but they need to have a high enough frequency response. Most seem to be 1 kHz or below.

Apologies for being gloomy, but is there a succession plan for Templot? I'm not a user yet, but may be after the next house move in a few years when I can have a permanent layout room.

It may be more than slightly wrong. It really depends on the multimeter. It's counter-intuitive in that cheaper ones can be better than dearer ones. Many do not sample the waveform. They have simple circuit that is only good for low frequency sine waves (e.g. 50/60 Hz derived form the mains). Even many true RMS meters do not have a frequency response adequate for DCC. It should be at least as good as any cheap multimeter. DCC uses cycles of 112 us and 200us, so appx 9 kHz and 5 kHz. It claims a sample rate of 1 Msps so it will be good for DCC.

Those don't look like the original pins, they look like they have been soldered on on place of a wiring harness. Whoever cut them short, needs a new pair of wire cutters :)

photo?

How thin will the thinnest parts be when scaled? Will it even print?

Actually there is a recommended standard in NMRA standard S-9.2.2 https://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-9.2.2_decoder_cvs_2012.07.pdf I believe (from posts by someone who was on the standards committee) that this was based on one manufacturers practice at the time, but the details are lost. The problems are that (a) it was standardised after decoders were already available with whatever the manufacturer did and, (b), manufacturers continue to ignore the DCC standards in all sorts of ways.

Like these https://uk.farnell.com/w/c/connectors/power-entry-connectors/dc-power-connectors-barrel-plugs-jacks/prl/results?gender=plug&sort=P_PRICE DC barrel connectors? You need to know the size, 2.1mm and 2.5mm being common, referring to the pin on the jack (socket on the equipment) and the hole in the plug (on the end of the power lead). If your connector is loose then you may be using a 2.5mm plug (larger hole) in a 2.1mm jack (smaller pin). Cut off the old plug and fit the new one, ensuring you connect the positive to the inner part (the hole). Or, try an adapter. This one has a socket (jack) for a 2.5mm plug and a 2.1mm plug https://cpc.farnell.com/pro-signal/ps11472/adaptor-2-1mm-socket-to-2-50mm/dp/CN22418 Or the problem is something completely different ...😀

PS Please open help>system console in JMRI and log the activity during a running session. Is there much else happening on the laptop at the same time as running trains?

What sort of laptop? I've only ever seen this on Raspberry Pis. It's not related to the cable. It happens when the machine is too busy to keep the packets flowing to the SPROG, e.g., moving windows around on screen with a Pi. It's really just a warning. What firmware version is the SPROG? You can see this in the console window.

Do you mean EZ Command https://www.Bachmann.co.uk/product/category/282/e-z-command-control-centre/36-501 ? The one that I have requires an AC supply. It doesn't work on DC.

I try to be :) Lots of questions, here's a selection... What's the layout wiring like? Do you have decent size bus wiring and frequent droppers to the track? Do the problems occur on particular sections of track, or when a particular loco (e.g., one that draws more current) is on a particular track section? Does it happen if only one loco is moving? If you add one loco at a time is there a limit, or is the behaviour more random? When things stop dead does the SPROG track power LED flash faster than normal? That would indicate some kind of overload. The SPROG is very sensitive. E.g., shorting on point frogs that are not "wired for DCC". You need at least a 2.5 Amp supply for the SPROG 3 and I would recommend 15V if it's OO. The Prodigy Advance seems to be 3.5 Amp, so maybe you are at the limit of the SPROG (although I doubt it). How many locos in total? What scale? Any known current hogs? You could wire a multimeter in series with the power input to the SPROG, set for DC current. It will not show any fast peaks but may give an indication of what is going on. The SPROG itself takes very little current. PS Help will come quicker if you put SPROG in the thread title. I only came across this by accident.

There's a 15 year old phone number on their blog page https://branchlines.blogspot.com/