Voltage too high?

[controller]

Hi,  I have a Gaugemaster Proidgy Advance controller. It is giving out almost 18 Volts (17.8) . I was installing lights into a Hornby BR 0-6-0 shunter with a Gaugemaster 4 function 8 pin decoder. When I applied power it toasted the decoder. Is there any way I can reduce the power output, as I am afraid it may damage other locos? The power output on the transformer is 13.8v. 

Thanks,

Controller.

[Noel]

1 hour ago, controller said:

Hi,  I have a Gaugemaster Proidgy Advance controller. It is giving out almost 18 Volts (17.8) . I was installing lights into a Hornby BR 0-6-0 shunter with a Gaugemaster 4 function 8 pin decoder. When I applied power it toasted the decoder. Is there any way I can reduce the power output, as I am afraid it may damage other locos? The power output on the transformer is 13.8v. 

Thanks,

Controller.

Did the loco run ok with the decoder before you added the lights?

Are you using a DCC ramp meter to measure the track voltage? An ordinary Ammeter/Multimeter won't read track voltage properly even if you set it to AC because of the DCC wave form.  Most DCC systems will output 15-18volts to the track. US systems tend to be closer to 15v whereas European gear such as Lenz, ESU, etc are closer to 18v.  DCC decoders will convert this to max 12v going to a loco motor.  I suspect the wiring for the lights may have been your problem rather than the Prodigy.  Some systems such as NCE have an adjustable pot inside the controller for fine tuning track voltage, but this is only for small changes and not enough to blow a decoder. Hope this helps.

[controller]

Thanks Noel, The loco ran fine with the old decoder, this was a new one I had purchased with the lights. I am using a multimeter  to read the voltage, so like you say, I may be getting a false reading . I will go over the wiring for the lights once more, perhaps that is the problem. Can't afford to be burning out too many decoders.

Thanks for your help,

Controller

[Dave]

You can't read DCC on a multimeter. DCC is DC with a modified Bi Polar square wave alternating. It will give you a false reading. The only accurate way is an oscilloscope. It would be unusual for the prodigy to put that voltage out, it's factory set to 14.5 volts.   

Have you had problems with any other decoders? Hornby can be problematic. Are you sure the LED's were wired correctly and is the decoder able to cope with the additional load?

[controller]

Thanks Dave, No I have never had any problems with any decoders, except for two or three I toasted when I started converting to dcc. The decoder I was using was a Gaugemaster 4 function 1.8 amp . It still works with the lights, and forward movement , but no reverse. I can see a small burn mark on the decoder. I checked all the wiring, and all is as it should be. I was having a bit of trouble trying to get the motor to turn, and when I checked it, there was also burn marks on that . As you know it is only a small motor on the 0-6-0 shunter, so I may have overloaded the whole lot. I will get a new motor and decoder and try again. The motor I am looking for is a Hornby DCC ready 0-6-0 motor assembly (modified),x8809m but they can not be got anywhere at the moment. I will watch ebay.

 

Thanks,

Controller.