Tornado A1 decoder failed?

[Engineer49]

I have a Bachmann Tornado A1 and I loaded the Hornby Tornado A1 DCC decoder to it. The controller is a Hornby Select.

Initially, the engine worked ok but after 1/2 hour the controller shut down because of overload.

Now as soon as the engine is on the rails it causes the controller to overload again. Other engines with different decoders are working ok so it does not appear to be the controller.

I have removed the DCC decoder and replaced the DCC blanking plate and run the engine successfulyy on DC. So the motor appears to work ok.

It would appear that the DCC decoder has a fault. Is there anything I can do to check the decoder?

 

 

[Chrissaf]

Without a decoder tester......then not really (I have the ESU 53900).

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You could try plugging the decoder in another loco just as a double check, but based upon what you have written so far, the fault is likely to transfer to the other test loco. If it works OK in another loco, then suspect that handling the decoder has dislodged something that was causing the fault, and try it again in the original loco chassis.

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A basic tester for the Hornby 8 pin decoders is easy enough to make at a fraction of the cost of commercial products. Such a tester was covered in the 2018 May edition of BRM magazine.

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Note that the article in BRM has an error in it, the article said that the long leg of the LED is negative. This is incorrect, the long leg is positive. I would also replace the tester power resistor suggested in the construction details of the article with a 12 volt motor to give visual confirmation that the decoder motor output is working correctly.

[96RAF]

Heres one I made earlier as Blue Peter used to say...although I also have the ESU device.

http://myweb.cytanet.com.cy/honnor/article4.html

No need to have anything except the motor and socket directly wired to each other and the controller. If it works then you know its likely the function outputs causing the decoder fault.

You could then add on the leds. If it works then the fault must be with the loco. Check the obvious like the decoder plug touching metal or a solder bridge at the loco socket.

Rob

[2e0dtoeric]

Minor tech problem with that, Rob - try getting a piece of veroboard from Maplins!  :-)

[96RAF]

Minor tech problem with that, Rob - try getting a piece of veroboard from Maplins!  :-)

Hence why I said just wire the socket direct to the motor and controller. I suppose I should raise an errata notice to the article referring folk to Companies House Archives for Maplins, although I would expect the average Joe to be able to source veroboard without further instruction, if not I lapse into despair.

Rob

[2e0dtoeric]

Judging by various forums (forii?) the 'average Joe' needs to be given the web address and the part number, and will still claim they can't find it! 😛