Locomotive Buzzing

[AUSLNER]

I recently input the Hornby TTS for the Castle Class into my Castle locomotive.  However it doesnt work! The locomotive just starts running immediately and making a high pitch sound.  I have no control over the locomotive.

I have tried another non-sound decoder and get the same problem. So i presume it must be a problem with the locomotive.  When i put the blanking plate in, the locomotive works fine like a dream!

I have read about changing the CVs for CV9 and so forth but none of that seems to make any difference at all i still get the same issue.

Has anyone else had similar experiences?  Not sure what to do now!

[Howbi]

You say CV9 I presume you mean CV29 where you can disable DC running........other than that you may have to unscrew the DCC socket and check the underside for any wiring that has been badly soldered and is touching an adjacent pin..................HB

[Fishmanoz]

For a start, what you are describing seems to be DC Runaway where the decoder can’t recognise the signal as being DCC so assumes it is DC and, as DCC always has full volts to the track, it takes off and can’t be stopped.  You can stop this symptom by turning off DC Running by subtracting 4 from the value of CV29. But this won’t make it work DCC. Poor DCC working is usually down to poor connection somewhere.  HB is suggesting it may be due to something in the socket, although the socket seems to work fine with the blanking plug. Is you track clean, and the wheels and are the pickups properly tensioned on the wheels?

 

Also are you still using your DC power connector or power rail?  These have a capacitor across the track which degrades the DCC signal. You can convert them to DCC by flipping open the black cover and clipping off the legs of the capacitor in there.  They still work fine for DC after that too.

 

Tell us how you go.

[AUSLNER]

For a start, what you are describing seems to be DC Runaway where the decoder can’t recognise the signal as being DCC so assumes it is DC and, as DCC always has full volts to the track, it takes off and can’t be stopped.  You can stop this symptom by turning off DC Running by subtracting 4 from the value of CV29. But this won’t make it work DCC. Poor DCC working is usually down to poor connection somewhere.  HB is suggesting it may be due to something in the socket, although the socket seems to work fine with the blanking plug. Is you track clean, and the wheels and are the pickups properly tensioned on the wheels?

 

Also are you still using your DC power connector or power rail?  These have a capacitor across the track which degrades the DCC signal. You can convert them to DCC by flipping open the black cover and clipping off the legs of the capacitor in there.  They still work fine for DC after that too.

 

Tell us how you go.

I have adjusted CV29 to 2, the default is 6 so as you said substracting4 from 6. Didn't work :-( the track is clean I cleaned it  a few days ago and it still looks pretty clean. All the pickups are properly tensioned. Still doesn't work. No DC power at all being used on the track. Im using the DCC power rail

[AUSLNER]

I tested the decoders on another loco and they work fine so it's definitely a problem with my locomotive

[AUSLNER]

I can confirm it is an issue with the locomotive itself.  I ran the tender of the castle with another loco, no troubles at all. ran the loco body of the castle with a tender from another loco i had the same issue as above.so there must be some wiring fault with the locomotive!

[96RAF]

There have been instances of locos and tenders being cross wired, i.e. loco left side wired to tender right side and vice versa but this always produces a dead short not exactly what we are seeing here.

 

If you are going down the route of fault finding please note that there was a problem with some of the TTS decoder requiring a reprogram by return to works at Hornby, although the fact the tender runs OK points more to a loco wiring fault as you say. Standard fault finding techniques should trace the fault, excepting that Hornby tends to use all black wires just to make things a tad more difficult.

 

Rob

[2e0dtoeric]

The 'buzzing' points to the loco getting AC to the motor, when it was expecting dc.

[Fishmanoz]

This is a puzzle.  Rob’s crossed wiring between tender and loco sounds good except it runs with the blanking plug fitted which pretty much rules crossed wiring out.

 

2e0 also seems to be right about the whine being due to DCC 10-12kHz track voltage going to the motor.  That would require wrong wiring of the decoder with pickup and motor connections swapped. That’s a possibility if the socket is miswired. So I would be starting there.