Last night a mate who's been in the hobby a couple of years brought over his Newqida 2-6-2T which had stopped working. It was the first loco he bought, and although he doesn't run it all that much anymore he likes to keep it alive - and it had refused to work on Sunday. A few quick tests suggested that the 7.2v NiCd battery pack which had come with it had died; the thing was fitted with Tamiya connectors and I had a 7.2v NiMH battery pack with the same connectors so the solution appeared to be change the battery. (Mistake number 1 - question should have been "why has the battery failed? Is that all that is wrong?")
On the blocks it ran fine for 15 minutes or thereabouts, so we thought "that's that" and were proceeding to the drinking stage of the night when I noticed smoke coming out of the chimney of the loco; which is not fitted with a smoke unit..........
Rapidly opened the smoke box door to find a mess of melted insulation in the battery leads. The battery was disconnected with only very minor burns to the fingers being sustained. After it cooled down I disassembled the beast to assess the damage - of course with hindsight that is what I should have done in the first place. Inside and unaffected by the short there were a number of wires whose insulation is in a parlous state, leading me to believe that the short was caused by degraded insulation leading to bare wires in the leads, possibly with a final fracture while I was playing around with getting the new battery (whose plug was a tight fit to the loco plug) connected.
Whether they were in that state all along or had evolved to it over the time Mike has owned the loco I don't know, but they are going to have to be changed - as will the battery leads obviously; and I am wondering if the old battery had in fact died because a short had occurred when it was at a low state of charge.
The loco will survive with a bit of work - luckily the electronics don't seem to have been fried, and the body has only a small amount of melt damage which is correctable. Even if there had been a complete melt down it was on a non flammable surface so it wouldn't have caused a more general fire, but it was still worrying and could be disastrous if it happened in a different environment. I would therefore strongly advise anybody with one of these locos which has a bit of age to it to have a look at the state of the wiring!
Steve
On the blocks it ran fine for 15 minutes or thereabouts, so we thought "that's that" and were proceeding to the drinking stage of the night when I noticed smoke coming out of the chimney of the loco; which is not fitted with a smoke unit..........
Rapidly opened the smoke box door to find a mess of melted insulation in the battery leads. The battery was disconnected with only very minor burns to the fingers being sustained. After it cooled down I disassembled the beast to assess the damage - of course with hindsight that is what I should have done in the first place. Inside and unaffected by the short there were a number of wires whose insulation is in a parlous state, leading me to believe that the short was caused by degraded insulation leading to bare wires in the leads, possibly with a final fracture while I was playing around with getting the new battery (whose plug was a tight fit to the loco plug) connected.
Whether they were in that state all along or had evolved to it over the time Mike has owned the loco I don't know, but they are going to have to be changed - as will the battery leads obviously; and I am wondering if the old battery had in fact died because a short had occurred when it was at a low state of charge.
The loco will survive with a bit of work - luckily the electronics don't seem to have been fried, and the body has only a small amount of melt damage which is correctable. Even if there had been a complete melt down it was on a non flammable surface so it wouldn't have caused a more general fire, but it was still worrying and could be disastrous if it happened in a different environment. I would therefore strongly advise anybody with one of these locos which has a bit of age to it to have a look at the state of the wiring!
Steve
Note to self. Keep using track power, and switch off at the wall before going to bed.
Already there... I run trains after sunset. I've also seen the light, I run trains during the daytime, too. :-X :-X :-X