For those old enough to remember black & white television: ITV 1957 to 1967. Google it if you are too young to remember!
Emergencies do arrive at one's door, as in the popular hospital soap, a sudden unforeseen occurrence needing immediate action:
'Well, it was like this, Guv, we reversed a rake of wooden-bodied minerals into the siding, and then the engine wouldn't move. Can't figure it out, the engine was running perfectly until then...wonder if the chip has gone?'
'Ah!' [the possibility of the chip having failed. I knew the loco was equipped with a Loksound V4] 'Did the sound perform okay?'
'Yes - it were working fine.
I was in the middle of commission work, routine surgery would have to be delayed, and so I took the patient in and set to work. Placing the Bachmann Austerity on the track produced a direct short indicated on the controller. To cut a long story short (excuse the pun) and finding no obvious visual cause of the short, a gradual disassembly of the loco was undertaken, including separating the soldered-in permanent wiring between loco and the tender which housed the Loksound and speaker; this was an early Austerity not DCC ready and had been converted by me some years ago to DCC sound, it was one of my favourite locos, and the clanking big end ring of an Austerity was well reproduced - I had heard many of them in my childhood, clanking past in the night on the old GW & GC mainline.
By separating the tender both physically and electrically from the loco it became clear the fault was confined to the loco itself; and moreover, the short-circuit did not exist with the chassis bottom plate removed, but screw the bottom plate back on and the fault was present; this has happened before with these Bachmann Austerity locos, and I was somewhat relieved to suspect that the Loksound V4 was undamaged, and would only require the soldering back of connections between loco and tender.
The fault in the chassis bottom plate is with the metal strips that carry the pick-ups to each wheel, with time they tend to bow upward toward axles number two and three until they create a short across either or both of these axles; the remedy is to drill out the plastic securing blobs (what else do you call melted blobs of plastic) at the front leading end so that the metal strips can be stretched out and secured down with two-part epoxy; the slots for the wiper contacts will have to be carefully widened with a file at the front end to accommodate the slightly re-positioned metal strips - it's only a fraction of a millimetre.
Once the two-part epoxy has cured off and the metal strips are fully flat and secure I paint the top surface of the strips with two coats of ladies' clear nail varnish to insulate them against any further contact with the axles; although hopefully the epoxy will keep them in place for many years to come. All that remains is to screw the bottom plate back on, track test that the short is no longer present, and reassemble and rewire the four connections between loco and tender. Job done.
The photo below shows the disassembled chassis parts; note the bottom plate is reversed in relation to the chassis in the photo. The right hand end of the bottom plate shows where the securing blobs of plastic have been drilled out, the slots for the wiper contacts enlarged marginally, and both metal strips secured down throughout their length with two-part epoxy. Both metal strips have received two coats of ladies' clear nail varnish to insulate their exposed metal surface: avoiding the soldered wire contact area in case these wires ever need replacing. You will note also the heavily modified tender chassis with additional wire holes and grouped ventilation holes underneath where the Loksound V4 sits on edge; the speaker sits over a rose of specially drilled holes; space is very limited under the tender body. The tender is permanently coupled to the loco when in situ through adaption of the original tender coupling. The original conversion involved a lot of work; now just careful soldering of four wires and general reassembly is all that is required to restore that lovely clanking sound.