It wasn't easy. The J39 is tender drive, with pickups on the tender wheels one side and loco wheels the other. The loco body and chassis are a single solid casting, and the tender body is entirely filled with motor and gears. No room in front of the motor or behind it. In the end the only way I could get it to fit was:
1. Remove the plastic shrink wrap from the chip, and wrap it with thin tape (I used some Tamiya masking tape). Snip the surplus lighting wires off the chip, tape it to the top of the motor, solder the two motor wires direct to the motor terminals, and connect one of the pickup wires to the tender chassis using the motor securing screw. The other pickup wire goes forward to the loco and is secured in the same way as the original loco-to-motor wire which it replaces.
2. Cut out the entire coal load area from the top of the tender. I tried using Dremel slitting discs but they clogged too easily. The tender body is cast in something a bit harder than whitemetal, but not much. So I chain-drilled round the coal load, then used a slitting disc to finish the job, and tidied the edges up with a file.
3. The drive unit will now fit in the tender body, but with the chip sticking up through the top. It doesn't actually protrude too far, and I plan to gently heat and bend a thin piece of Plastikard to cover it, with a thin layer of finely crushed coal on top.
So having got the chip more or less installed I found a couple of old bits of track, soldered two wires to the end, connected up the DCC controller, placed the loco on the track and... nothing happened. Even though the default address is 03 on both the controller and the chip, they didn't want to talk to each other. Having checked that everything was connected properly, I reprogrammed the chip address to 02, and my J39 moved for the first time in about ten years.
I still had plenty to do though. Firstly there was an intermittent short, which I traced to the tender sideframes being bent inwards slightly. One of the non-pickup wheels was rubbing on the live frame. That was easy enough to fix, but then I found that, despite much cleaning of wheels and track, the loco kept stalling. After more dismantling and fiddling I thought it might be that the axles on the loco were not making reliable electrical contact with the chassis. I inserted a couple of lengths of bent phosphor-bronze strip in the channels that Union Mills thoughtfully provided above the leading and trailing axles, the result being a sprung chassis of sorts, and far more reliable electrical contact. So I now have reliable slow running, at least on a short length of straight track...
I am still getting used to the stubby little joystick on the Bachmann controller. It seems to increase loco speed far more readily than decreasing it. Following the instructions with the Digitrax chip I played about with some of the voltage settings which made the loco more controllable, but I still ran off the end of the track quite a few times. I think I just need to get used to a different way of controlling trains: I have always used H&M controllers in the past, with a large rotary knob.
So to commemorate the occasion, here is a photograph of Belstone's first train - a very unfinished J39 with a Peco mineral wagon, a Parkside kit-built BR 12 ton van, and a Peco tube wagon which I think dates back to the late 1960s. Time to start thinking about buying some track and points.
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