To all you experts out there,

I need some advice on a new problem that I have encountered while adding a new mfx loco (39498) to my layout.
Essentially this loco behaves as in should and has no problem registering with my updated cs3 ( now running 2.52). However I have one of my booster sections controlling a 7286 turntable and bridge section in combination with a Dec-TT decoder from Littfinski. Up to this point I have never had an issue sending commands to other locos while on the bridge deck. When the 39498 loco hits the centre bridge of the turntable it becomes completely unresponsive to any commands sent to it, and I have to push it off the bridge section before it starts up again (, although it can travel over the bridge deck happily). All my other locomotives ( including other mfx locos )work without a hitch and respond accordingly.
Outside of the turntable, this locomotive runs beautifully and doesn’t miss a beat.!
I have tried deleting the loco and re- registering and rebooting several times to no avail. I was wondering if a CV setting might be problem? But what CV..? I have upgraded the locos firmware and factory defaulted it, twice.!
If anyone has any ideas then it would be greatly appreciated.

Many thanks
Steve

When you start turnout table do locomotive have still contact on the bridge? Could be fault at pick up shoe or wheel contact.

When your loco stand on the bridge i belive You have bad contact on the bridge on a point. Clean the bridge by use cloth.

Thanks KiwiAlan,
While the loco is stationary in the centre of the turntable all functions that where operating prior to entry, remain in that condition . In this case, lights are on but sending a off command the loco just ignores it..all commands are ignored while parked up on the bridge..cannot reverse, and cannot add speed steps…totally unresponsive.!
I don’t believe it’s a contact issue as pushing the loco ( manually) off the deck till it touches the metal material either side of the turntable the loco will respond as normal.
I think I am going to have to rewire the turntable bridge and power the centre deck with a different power feed , while keeping the turntable decoder as it currently configured.
Just very weird that only this loco is having problems while all others ( approx 40 other locos) operate without a hitch..!!!

Here is a little known DCC fact that may explain your situation:

Could it be that you have accidentally reversed the phase of the digital voltage to the bridge - eg: black (or brown) to the central rail on the bridge and red to the running rails. You'd think that there would be a short when the loco crosses over from the feeder track onto the TT bridge. But that apparently is not the case.

While the DCC voltage (mfx or the old mm) is theoretically AC it is offset from 0 voltage by about 9 volts DC. I have read and also come across decoders that are sensitive to this offset. If it's backward, there would still be power on the bridges center rail and the light of the loco will remain on. But all commands will be ignored. The old K83's or K84's don't seem to care but an older ESU decoder in one of my Roco loks is. Took me month's to figure that one out (even bought an oscilloscope because of it).

Ideally the track power to the TT bridge should be wired to the TT feeder track power.

Just my 5 cents worth.

-=tom=-