Bachmann Spectrum 80 ton three truck Shay electrical faults

Model Railroader Electronics and DCC
21

Multimeter confirms the fault is in the axle to side frame continuity.

The polarity isolation is at the axle driven gear side. The rest of the axle is electrically connected to the left side, non driven.

There’s an obvious insulating ring just inboard of the gear driven right hand wheel.

My guess is Bachmann elected to build a wheel with integral crown gear and insulated stub axle pressed onto the left hand axle and wheel.

Multimeter confirms this electrically.

Multimeter confirms intermittent conductivity wheel to axle.

22

Whomever guessed paint in the axle sockets was apparently correct.

I had to dismantle the center truck, again (I’m getting quite adept at reassembly, disassembly happens more or less automatically once you back out the one tiny Phillips head screw), to repaired an axle retaining clip. The one pin snapped so I tapped the hole, extending thechole and the thresding through the plastic clip, and inserted an 00-90 brass machine screw from Hob-Its, clipping off the head and filing the stub flush.

Anyway, while it was apart I remembered someone suggesting paint in the axle holes and that turned out to be correct. Also on some axle stub ends which was easier to clean off. Reassembled with conductalube now accurately placed right in the axle holes and this Shay runs like new again.

I am pleased.

23

That would be Randy. Glad it worked out.

Simon

24

Bless his soul.