Graham Farish Class 14 DCC Conversion

[dripfedfred]

I recently converted a newly released Graham Farish Class 14. Although very successfull when complete there were a few problems in the process as follows

 

Firstly, there is no room within the shell for a decoder. I located it in the cab and had to remove the internal plastic trim to make room, its barely visible and doesn't detract from the fine external features of the model which are quite superb. The decoder I used was a digitrax dz125. One thing I noted was that a slimmer decoder may possibly fit within the shell in a lateral position but it would be very tight indeed. This of course would retain the trim in the cab

 

Secondly, although this is the same basic chassis and motor type as the 04 and the newer 08, Farish have introduced a very close metal lug connected to the live chassis which makes it impossible to isolate the motor without milling this away. It involves very close work with a dremel next to the circuit board.

 

Thirdly, removal of the shell interferes with some of the intricate metal pipework which fits directly into the chassis and this is very difficult.

 

Finally, as with all of this chassis type, only 4 pickups had arrived in contact with the wheels. This is something you don't notice on dc as the loco's momentum just drives through it. On dcc it is immediately obvious with regular stalling so I removed the pickups and adjusted them correctly. This seams to be a real problem as the pickups on this chassis type are extremely fragile and at least half of the similar locos I have seen have arrived new with only 3 or 4 of the pickups actually contacting the wheels. The new chassis 04 and 08 models are exactly the same.

 

If you would like to view a test run of this particular model it can be seen here

 

Douglas Stewart

 

 

 

 

[Kris]

Interesting to hear the way that you have approached this and the issues that you have found.

[locoworks]

i did mine a bit different and kept the cab detail. my pickups were ok and didn't need tweaking.

 

 

Remove the body by undoing the 4 small screws in the corners and ease the chassis out. Remove from the chassis block the central weight/gear cover by undoing the screw at the front. Undo the orange wire tag by removing the screw from underneath the chassis and keeping the little nut safe. Remove the tiny screw at the rear of the chassis that holds the electrical contact and plastic motor cradle to the chassis. ( the exploded view in the service sheet with the loco shows a different electrical contact arrangement like the 04 ) the motor and cradle can now be removed. Remove the motor from the cradle by undoing the 2 CSK screws at the front of the motor and easing the motor out. The PCB can now be modified. Remove the surface mount components and excess copper clad from the PCB leaving something like the picture, be sure to remove a little at the bottom left to be sure no shorts could occur between there and the chassis. Reassemble the motor into the cradle. Remove the small cast peg from the chassis left rear that helps apply pressure to the electrical contact on the motor. The chassis needs to have metal removed to create a space for a decoder. I used a CT electronics DCX75 as they are both thin and narrow. ( a DZ125 is too wide ) the thickness is less of an issue as more depth of metal could be removed to give clearance. To avoid any metal filings from getting into the gears i wrapped the whole chassis in cling film leaving just the area to be removed exposed. I used a finger sander to do this and did it in stages so as not to build up too much heat in the chassis block. This metal removal meant that the original tag and insulation moulding for the original orange wire needed lowering to clear the bottom of the decoder. This is where the RED wire will be connected to. To fix the BLACK wire to the chassis block i made a similar tag to the factory item and this goes under the screw that holds the weight/gear cover on.. As two wires now need to be routed from the front to the rear i cut another groove into the top of the weight/gear cover to allow for this. It is needed as the cab detail protrudes lower than the bonnet tops inside the body. The motor and weight/gear cover are put back on the chassis. I temporarily taped the decoder into place to allow me to cut the wires on the decoder to suitable lengths. I totally removed the white and yellow wires as they are not needed due to the lack of lights. The decoder was then removed and the two tags for the BLACK and RED wires soldered on. The weight/gear cover screw is removed and the two tags connected to the RED and BLACK wires are screwed into the appropriate places. The decoder is then fixed properly into possition, i used thin foam tape for this from a lenz mini. I was going to use just double sided tape but my sanding away of metal did not leave a flat enough area for this to be viable. The ORANGE wire goes to where the original orange wire went so needs to be in the original groove on the weight on the right side, and the GREY wire in the left side groove. These are taped to the weight and again taped to the motor to keep them in place. The ends are then soldered onto the PCB. The PCB is then covered in insulation tape so it cannot short against the metal body. BEFORE the body is replaced insulation needs to be in place so the decoder cannot short against the body once assembled. To allow a better airflow over the decoder to aid cooling i chose to put the insulation onto the bonnet inner at the appropriate place instead of over the decoder itself. The chassis was tested without the body on first and worked ok. The body was then fitted and the loco tested again. It all went well.