Hello Rich,
Just read your post. I have done a few conversions to date, both steam and diesel.
The Farish 66 was relatively simple. just remove the 2 jumper clips on the P.C.B. that enable D.C. running. Position the chip (I used a Lenz Gold Mini) where it sits, first stick some electrical tape across the chassis to avoid any shorts. Trim the wires to the correct length, and carefully solder them to to respective contacts on the P.C.B.
Farish Class 47's are a little more tricky, but not difficult. The chassis halves are part of the current collection, and need to be isolated from the motor contacts. What I do is split the chassis in half, havin first noted the position and relation of the bogies. They come apart when the chassis is split, and bits are easily lost! Once I have two chassis pieces, I use a small file to mill away the part of the chassis that contacts the motor brushes. When you think the clearence is adequate, refit the motor and check with a multi-meter to ensure that there are no short circuits. I then solder two short lengths of wire, about 75mm, one to each motor brush. Re-assembly the complete chassis, and run these two wires upwards between the chassis halves, ensuring that the motor is not fouled. Insulate the top of the chassis, where the chip is to be positioned with electrical tape. The method I use for collecting the current for the supply to the chip is as follows. It is not hi-tech or very pretty, but it works for me. I cut wilth a scaple, a small piece of balsa, about 15mm x 4mm x 4mm. Bear about 4mm of the pick up wires for the chip, and tin the exposed wire. Then I superglue the wires to opposite sides of the balsa. Slacken off the screws that hold the chassis together. Not too much, just enough to get the bals and the wires trapped between the chassis sides. Then retighten the screws. Join the wires from the chip for the motor connection, to the ones running up between the chassis halves and cover with heat shrink. Then check the loco on your programming track
Farish H.S.T.s with the centre mounted motor are quite simple. All you have to to is interrupt the current collection from each bogie and put the feeds to the chip. Then the output from the chip goes to the wires to the motor. Insulating where necessary.
Now for 0-6-0 chassis like the 08 of steam loco's A3's etc., this site may help
http://www.jigerspe.demon.co.uk/theme_2.html
You need to strip the chassis down a fair bit. What i do is ream out the bottom brush holder hole large enough to accept the brush holder that I have covered with heatshrink tube, to insulate it. Don't make the hole too big, as the brush holder needs to be a fairly tight push fit. Solder a short length of wire to the brush holder spring clip, about 75mm, for contacting to the chip later. What I do then is insulate the side of the chassis with black electrical tape, again, not pretty, but it works for me, , then refit the spring clip and check for shorts. The electrical pick-ups come
from:-
a) the wire going to the capacitor at the front of the loco, which I remove.
the bolt that comes from the base plate up through the chassis
so this is the two places you get your feed. You need to join the outputs from the chip to the wire from the bottom brush holder, and solder one to the top brush holder. Checking all the time with a meter.
I uses Lenz Gold Mini's, Digitrax DZ123, and T.C.S. M1 chips, they are all roughly the same size.
I hope that this has helped.
Kevin