Dead loco decoder?

[rhpd42002]

This afternoon I was running my Stewart, GN F-7, pulling a passenger train, when it just stopped.
It has a hard wired, DZ-123 decoder and it's been there for well over 5 years.
I cleaned the track and tried to clean the loco wheels, but even at speed step 99, the wheels barely turned. The headlight would come on, then not and now it won't move at all, nor will the headlight come on. The decoder does not appear fried, but I will have to de-solder it and re-solder in a new decoder to see if that decoder is the problem.
Anyone have this happen to them before? There was no short or derailment prior to the loco just coming to a halt. In fact there was a sound equipped loco idling on another track and it kept idling away when this happened. I didn't see or smell any "magic smoke" either.
I have too many locos in the shop as it is, awaiting repairs, let alone new ones that don't even have decoders installed, yet!!

[bnsf971]

I had a Stewart F7 that started shutting down when running, and not going very fast. It turned out to be a case of bad electrical connections to the track. I cleaned the wheels, which helped a little, then I took apart the trucks and cleaned the contacts for the wheels. That helped a lot more. I finally wired the matching dummy B unit's hard-wired trucks to the A unit, and had no more trouble.


I also remember a Kato motor that had worn out motor brushes that did similar things. The extra current required by the bad contact from the brushes overloaded the decoder, which shut down until it cooled off.

[rhpd42002]

Terry,
when I get time, a "tear down" will be in order for that loco. The only other strange thing before it quit moving was as I turned up the throttle knob, the headlight would get dimmer! Quite odd.

[bnsf971]

Aug 13, 2012 3:44:03 GMT -8 rhpd42002 said:

Terry,
when I get time, a "tear down" will be in order for that loco. The only other strange thing before it quit moving was as I turned up the throttle knob, the headlight would get dimmer! Quite odd.

Sounds like an overload. The decoder was giving all it had, plus more.