I think I have a problem with my small (2.2m x 1.5m)C track layout. I am running it with a Marklin 60VA transformer and 2 Mobile Stations.
the output voltage at the transformer measures 16.4V AC but the voltage on the track that is coming from the MS is only 10.4V AC (voltage measured on the feeder track). this seems too low to me and certainly I have problems if I run 2 mfx locos with lights and sound on. I have searched the forum to see if anybody has discussed this before, but could not find info on exactly my problem.
Has anybody got experience of track voltages from MS? Do I need to invest in a 6021/CS/IB etc.?

#1: Not all volt meters can be used to monitor track voltage. (I get two totally different and totally meaningless reading with the red cable at the center stud vs. black cable on the center stud.) Which voltage readings do you get from your MS? Track voltage should be 18+ V with no trains on the track.
#2: The capacitor in the ugly box is pretty small.

What problems do you have? The MS will switch off track voltage if it detects overload. So if your trains start to stutter this could be a problem with MS overload.
If you don't have problems with stuttering trains, but with dropping track voltage: a switching DC power supply (18 through 22 V) is the best solution against this problem; bigger capacitors can also help.
I have a laptop power supply with a fitting plug - track voltage is more stable with it than with the orignal M* transformer.

Just before my mobile station blew the voltage dropped to around 9 to 10 it had been around 13 to 14. About two days later after the voltage dropped it stopped working. Marklin quickly replaced my MS but while it was out for replacement I bought a 6021 off of ebay. Now I only use the MS for a Programing Track to set addresses and speed properties.

Don't do this. A capacitor on the digital signal is close to a short. I've seen a capacitor placed between red and brown wires causing an extra absorption of 1 A.
A more meaningful reading can be obtained by placing a rectifier bridge on the rails and measuring its rectified output with a DC voltmeter. It's some sort of peak voltmeter, just add 1 V to reading to account for diode voltage drop.
On my IB I've seen terrible voltage drops with load. Peak output voltage drops of ~3 V per A of load. The reason seems to be in not enough filtering of power supply, observing the output of the IB with an oscilloscope I see a big ripple at 50 Hz (I'm in Europe) increasing with load.

Regards

Hi friends,

measuring digital voltages and currents with a simple volt meter is not so easy, as it is neither a DC nor an AC voltage/current, as rugauer has already said. And it's high frequency, where many standard electronic devices fail to work correctly.

Nevertheless, it is quite easy to obtain correct results, it you transform the digital signal to clean DC, as is shown in the following circuit:


As you see, it is a simple rectifier bridge. However, you can't use an ordinary rectifier but you need really fast switching diodes, e.g. the Schottky diode indicated in the diagram or equivalent. Standard 1 N 400x diodes won't do, but leave too mich high frequency at the volt meter inputs.

The voltmeter in this circuit must be adjusted to a DC measurement range, and it will show the correct absolute voltage at the tracks.

With this circuit, you may also determine the current flowing in your digital circuit. Simply insert the rectifier in the red wire (between the MS/CS/CU/IB output and the center rail). The multimeter must be adjusted for a DC current range. The diodes should be able to withstand the current flowing. With the BVY 2100 you can use this device for currents up to 2 A.

Total cost for the diodes is perhaps 3 - 4 EUR.

Hans Martin

Very sad to hear from your MS burning. Please tell us more how this happenend so we can learn from it. I hope you did not connect two MS with two ugly boxes to the same track?
Henk.