Can this chassis be converted to DCC?

If so, what needs to go where, my experience and knowledge is limited in these matters but I decided to give it a try.  I am using a Hornby 4 function decoder.

Engine ran well on DC previously.

Its the top chassis in this picture.

I removed the black wire with spade grips and the capacitor from the loco firstly.

My understanding was to solder, black onto the left rail pickup (looking from rear of loco) (this wasn't connected to anything) Red to right rail, Grey to Screw on top, Orange to metal bar on top of chassis.

I only get a Short Circuit as soon as I put onto live track though. 

Is this something to do with poor isolation, or perhaps to do with the fact the one side pick up wasn't connected to anything (on the face of it anyway)

I realize it is an old loco, but if I can get it working DCC I would like to, and the practice experience cant do me any harm.

If I have to buy another decoder, as I've fried the current one, so be it.

Many Thanks
6up

Know nothing of Hornby 00 stuff, but guessing from this statement . . .

Quote from: 6up on May 24, 2015, 09:10:56 PM
. . . or perhaps to do with the fact the one side pick up wasn't connected to anything (on the face of it anyway)

. . . that the pickup in question routes power through the chassis to one side of the motor, as this is the way many earlier N gauge locos worked. If this is the case then one side of your track-to-motor circuit is completely bypassing the decoder hence the short circuit.

What you really need to do is make sure that the motor is completely isolated from the chassis and connect the orange and grey wires there making sure nothing can touch the chassis.


Paul

Many Thanks Paul, I did wonder if the pickup went straight through the chassis in some way. 

If I can completely isolate the motor and the orange and grey wires, would the black wire then still connect to the pick up?

6up

Yes.

Might involve some surgery though to isolate the motor - the Graham Farish split-chassis locos used part of the casting as a direct contact to the motor, the only way to get around this was to remove the offending part of the casting with a Dremel


Paul

Thanks all,

I spent most of last night insulating the wires/body/wheels from each other but to no avail as I was still having the short circuit problem. 

I then decided to de-solder the decoder from the chassis, and test the motor with a dc controller which worked fine.

Next I soldered the orange and grey wires directly to the motor connections I had just tested with DC, put the red and black wires on to the track, and got the same short circuit problem as before.

So my problem, at least partially, is within the decoder or wiring itself.

I cant see any of the wires I,m not using touching each other so I'm at a loss to work out whats going on?

Have I damaged the decoder in some way that could cause this?

Any help is greatly appreciated no matter how small.

Kind Regards

6up