I have recently returned to the hobby . I build Bowser and Pennline steam which are heavy lead engines that when running correctly can draw 1 amp under heavy load. I have been using Digitrax DH126 basic 1.5 amp decoders and have had several decoders fail as well as give wierd response to intermitten track shorts, like engines just deciding to start moving on thier own. Before I left the hobby I had used basic Digitrax decoders with good sucess and pretty much all decoder failures I could trace back to a fault to some type, motor failure, chafed/shorted wire, ect. These DH126 failures not so much. I am very disappointed in these new decoders. What are you all using for test/beater decoders?
You said that these loco’s are drawing 1 amp while running, what is the amp draw when stalled? This may be a problem. You need to stall the motor to see the correct load the decoder must handle. If your loco is starting to run on its own , I would guess the decoder has shorted some how.
Found a couple MRC G scale 2.5A decoders on Fleabay for. $16ea, will use them during mechanism debugging and run in. But several of the DH126 failures were completely out of the blue, no short or stall. One in fact happened on a H8 consolidation that I had remotored with a can, it had been running for weeks then out of no where just stopped, could not write any cv and reading returned garbage. Threw in another decoder and she has been running good ever since.
