NCE Power Cab Issue

Hi all, Hoping someone can help me please.
I recently completed the addition of the Cobalt IP Digital point motors to my layout, all 25 of them.
They tested okay when being installed by being powered from the original track bus before I added an accessory bus to power them.

I've added all the necessary droppers / feeds etc and decided that I would again test them individually on both buses to check frog polarity etc. therefore only adding the relevant wiring as I go.

When I then added the Power Cab to the system I was frustrated to see that I had a 'short' somewhere but couldn't understand why as the only power to the layout was what originally worked.

So I've basically removed all the wiring from the track bus with the exception of one pair of droppers.

Now when I attach the Power Cab I'm getting a continuous high pitched buzzing- the led is lit and the cab displays the correct info. This stops if i remove the track feed from the rear of the pcp - the led remains lit and the cab still displays the correct info.

Any suggestions / advice please.

Thanks
Malc

 

Hi Ron, I'm happy with the wiring configuration for the frog switching - it's this buzzing from the Power Cab I'm concerned about

Malc

 

Hi Kim.

The accessory bus will be powered by the NCE system, I've split the power feed into two - one for the track bus and one for the accessory bus. However my testing of the point motors only used the track bus to address them etc. The latest testing has started with only the track bus connected because i was getting the Power Cab screen flashing which from past experience indicates a 'short' somewhere, and now I get this buzzing as described above.

 

Hi Paul. The track bus is the only item attached to the PowerCab, nothing else.

Malc