Bachmann Spectrum problem ?

[firemansteve]

I purchased a spectrum dash 8-40 cw dcc ready. I have not installed a decoder yet. I placed it on my dcc layout and it goes forward and then stops goes forward and then stops and keeps repeating this. I have two other non dcc spectrum locomotives that I run on this same track and they operate just fine. I placed it on a small DC track and it operates just fine. Anybody have any ideas where to begin to look for problem? Any help would be appreciated. Thanks

[Jim Banner]

I suspect the problem is your DCC booster detecting a short circuit, or what it interprets as a short circuit.  If you connect a small lamp, like a grain-of-wheat bulb, across the rails, does it turn off and on as the locomotive stops and goes?  If so, it is your booster cutting out and cutting back in.

The DCC signal might be shorted by the capacitors in the locomotive.  This usually happens, if it happens at all, with the motor pulses put out by an installed decoder.  I have not heard of this happening with a non-decoder locomotive on a DCC track, but with a light enough booster, this might be possible.  What type of DCC system are you using?

It is more likely that a mechanical drag or a partial electrical short circuit is responsible for overloading your booster.  How much current does this locomotive draw on your dc track?  Running light at 12 volts, it should not exceed .5 amps.  If it does, you have a problem, either electrical or mechanical.

To measure the current, you can use an ohm-volt-amp meter.  Digital ones can be had for around $15, or even less on sale.  They are an invaluable tool when working on locomotives, not only for trouble shooting, but also for measuring motor and lamp currents and checking for proper isolation when installing decoders.   

[firemansteve]

I am using a digitrax zephyr. How do I go about testing the voltage on this locomotive. You will have to excuse me but I am very new to this stuff. Thanks

[Hoople]

I am using a digitrax zephyr. How do I go about testing the voltage on this locomotive. You will have to excuse me but I am very new to this stuff. Thanks

You'll need a voltometer (Is that what it's called? I'm only 12 and don't know everything.) which I belive is available at radio shack.