First i measured the voltage on track with a digital meter and had 20 v AC.After reading this thread http://www.trains.com/TRC/CS/forums/854312/ShowPost.aspx that you say that we can’t have a proper measurment from the track ,I measured the voltage on the blue and green cable of the decoder and it was 19,5 v DC.Also i measured it on the bulb os the loco and it was the same.
So it seems that it is to much!I have a Roco digital system and i can not regulate the voltage.What shouid i do?If it stays that way is there going to be any serious problem?
Because i can’t unterstand why the manufacture builded like that.
Like to help, but not familiar with the Roco system. You could always put a resistor in line with one of the feeds. Should probably contact the manufacturer first. There should be a list of specifications that came with the system that shows the proper voltage to the decoder. Keep us informed of the outcome. Jerry
Your fancy ‘super meter’ cannot accurately measure DCC voltage. The problem is that most meters are calibrated to meaure the RMS value of AC voltage at 60 hz. Your DCC signal is at much higher freaquency. If you really want an accurate measurement, try using ths:
The ROCO system is well known for a high voltage. You can not regulate it and have to life with it.
It will cause no problems with most decoders. However, you should be prepared to get your decoders better ventilated than the average use (with adjustable DCC supply).
He measure the output of the decoder to the lights, which is a pretty good way of getting a reasonable estimate of the track voltage, since it is more or less the rectified signal.
Railroad-
Is this HO scale? If so, it may not be really too bad, though it sounds a bit high. I’d have to do some reading. That voltage is well within what decoders are required by the standards to handle, but that does not mean that the motor can handle it. I looked at the Roco web sire, but didn’t see any documentation on the system at all, so I can’t say what it is designed to do. Does the manual have any specifications?
Sounds like the voice of experience. The decoders should be able to handle it. I was wondering, does this system use an external supply to power the booster? I was thinking maybe a lower voltage supply might help, if so. But I don’t have enough info to really say that.
I used a digital multi-meter to test my voltage a few months back and was startled to find a reading of 20 volts. Previous readings using that same instrument were nearer to 16 volts.
What I found, upon inspection, is that I had inadvertently flicked the scale/voltage switch on my Digitrax DB 150 up with the power switch one session, meaning that the voltage the unit put out to the track rose from a mean of 16 v to 20 v. since that higher position was for O scale. I have no idea how long that had been the case…it might have been one session, it might have been three weeks. In any event, there was no apparent deleterious effect to any of my Tsunami, Loksound, and QSI decoders. None were scrambled in any way, and each locomotive continues to run like a champ to this day.
So, don’t worry. And trust your multimeter to afford you a close (good enough) approximation of the true voltage going to your track.
Yes, the ROCO Lok Mouse is very wide used here in Germany. It’s a very well accepted DCC entry system for a reasonable price.
Because it is often used by newcomers there are tons of entries in German forums. Most are about the problems how to program the CVs without a display of the actual value stored and the others are about hot decoders.
However, the decoders do fine if there is enough ventilation. It becomes only critical if you know the decoder manufacture did work at the edge of the specs. That decoders have a tendency to fail with the ROCO Lok Mouse.
ps. “Lok” is the comon German abbreviation for locomotive.
Generally with regulated voltage circuits, which most DCC units use, the input voltage is not directly related to the output voltage. On my Lenz with a 15 VAC input it can be set to put out several desired voltages. Originally, I ran at 17.5V output to match the club, but have recently changed it to 14.7V.
Actually, something like CSX_Robert suggested would be a cheap and easy fix. Based on the standards, the system isn’t really wrong, it is just that some decoders are unable to handle it. Strictly speaking it is the problem of the decoder, but that doesn’t really help if it blows up!
Is there a load on the system when you test the voltage?
If there is no load, there can be a higher voltage indicated, because there is no voltage drop. Digital multimeters introduce very little load. Cheap meters, especially analog ones, can introduce enough of a load to skew the readings.
DMMs are not too good at higher frequencies. They start to do strange things. Most of them expect to see a nice sine wave, and a DCC signal appears to them as a very distorted wave. A lot of distortion can also have a negative impact on the accuracy of a meter.
A simple test would be to check the voltage of a fresh 9V battery. Can give you a good idea of how accurate the meter is.
Well, I always thought that, and pretty much still do. But Kato’s (I thin kI’m remembering right)N scale motors specifically ask for no more than 12. Also, light bulbs won’t last as long.
But he also looked at the output of a decoder. And someone who seem sto know about this sytems confirms. What is frustrating is that by all the standards it should be fine, but some decoders don’t like it anyway.