Author Topic: My Bachmann decoder is dead?  (Read 364 times)

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rva1945

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My Bachmann decoder is dead?
« on: October 14, 2018, 10:59:57 AM »
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Hi:

Suddenly, a Bachmann 2fn decoder ceased to work. It kept is address as it responded to the light on/off command, but no movement from the motor. The programmer doesn't identify it, even after writing any value to CV 8.

I use DCCpp (throttles) and JMRI (programmer).

After writing the CV 8 it now doesn't respond to the light on/off command, sure it lost its address.

I put it in the programming track and try to write in to CV 8, and it returns -1 which means "verification read fails".

My other 4 locomotives work well, the programmer identifies them in case I test that feature.

What could have happened?


jdcolombo

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Re: My Bachmann decoder is dead?
« Reply #1 on: October 14, 2018, 12:05:39 PM »
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Suspect that the connection to the motor is bad or that the decoder's motor control circuits have died.  More likely the former, though.

What engine is this decoder in?

In order to read/write to a decoder on a programming track, you must get an "ACK" signal back from the decoder, which usually involves pulsing the motor.  If the motor isn't connected, you will get read/write errors - and of course, the engine won't run, though the lights may work (exactly what you are seeing).

If you did manage to do a factory reset, then the DCC address should be back to "03".

Check the connections between the decoder and motor - and check that the motor itself works (you can do this by using a 9v battery with wires - make sure the decoder is disconnected, attach the battery wires, and see if the motor runs).  If the motor itself is good, check connections between it and the decoder.  If that still produces no joy, you probably have a bad decoder.

John C.

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Re: My Bachmann decoder is dead?
« Reply #2 on: October 14, 2018, 12:56:34 PM »
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What model is this? I've experienced board-level intermittent failures with similar behaviors. IOW, not the decoder itself, but the connections in between the frame and the decoder. Bachmann has an awful lot of "extra" components on their main board to deal with European regulations.

[snark]

Of course, I would interpret this as a celestial message to replace it with a real, quality decoder. Bachmann's decoders are... well... :|

[/snark]
...mike

http://www.gibboncozadandwestern.com

We don't make mistakes, we have happy accidents. We just don't tell anybody. -Bob Ross

rva1945

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Re: My Bachmann decoder is dead?
« Reply #3 on: October 14, 2018, 02:56:15 PM »
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FIXED.
During one of my tries, while the programmer was trying write CVs (to no avail), I took the loco from the rails for 1 second and put it back and then I could hear the motor buzzing. Then it worked as a charm.
As far as I can remember yesterday another loco produced a short while this F7 was running (on a Bachmann decoder), though it was not the only one, as there was another on a Digitraxx and another one on a LDH (this one made in Argentina, NMRA ID no. 56). No doubt the Bachmann is more sensitive, as this has happened before. But the loco that produced the short has a Bachmann and it was not affected!