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I picked up a couple of H0 Bachmann US diesels for my next layout which will be US freight. One was DCC friendly and just required a decoder plugging in. The other was a £20 B23/B30. It has a live chassis but the motor is isolated. The bottom contact is simply a brass flat strip which contacts the chassis. Stripping down is quite easy involving removal (two screws) of the diesel tank then a further two screws which attach the chassis and plastic body. Three wires to the simple circuit board screwed to the top of the chassis have to be unsoldered, the circuit board removed (two screws) followed by the top strap to the chassis (two screws), with care the motor and flywheel assembly can be lifted out without removing the bogies.
The loose brass commutator connection can be straightened out, soldered to a suitable wire and covered with heat shrink tubing. The motor is then carefully re-located with the new wire up the side. Refit the top strap and circuit board and connect the two motor wires to the grey and orange (no particular way round) resolder all the previous removed wires and connect the black and red decoder wires to the two parallel strips running the length of the circuit card (again no particular way round as you can programme forward and reverse afterwards). I didn't bother with the lights for now but maybe later, I believe there should be resisters fitted across the LEDs, at the moment both lights are permanently on. There is plenty of room for the decoder to lie on top of the circuit board, suitably insulated of course.
For the price I was quite surprised to find that the loco was fitted with a 5 pole skew wound motor.
The running is very good, in fact much better than my GP40 which came DCC fitted for £23 from the same source.
Brian
The loose brass commutator connection can be straightened out, soldered to a suitable wire and covered with heat shrink tubing. The motor is then carefully re-located with the new wire up the side. Refit the top strap and circuit board and connect the two motor wires to the grey and orange (no particular way round) resolder all the previous removed wires and connect the black and red decoder wires to the two parallel strips running the length of the circuit card (again no particular way round as you can programme forward and reverse afterwards). I didn't bother with the lights for now but maybe later, I believe there should be resisters fitted across the LEDs, at the moment both lights are permanently on. There is plenty of room for the decoder to lie on top of the circuit board, suitably insulated of course.
For the price I was quite surprised to find that the loco was fitted with a 5 pole skew wound motor.
The running is very good, in fact much better than my GP40 which came DCC fitted for £23 from the same source.
Brian
