I realize probably 95% of people using the Forum are day-to-day working with the higher level Command systems (TMCC, DCS, Legacy, etc.) and probably consider these cheapie "Lionel Jct." starter sets as throwaways. So maybe I won't get a response here. But my grand kids LOVE these sets and especially the girls now have an interest in O-gauge trains, whereas without their PetShop sets, they likely wouldn't. (We are obviously hoping this interest will blossom into more sustained interest; the Disney sets and others are out out of reach of their parents' budgets at this time.)
OK, we have a dead Lionel HKYF12-180060T "Toy Transformer" (actually a power pack, since output is DC: 18Volts @ 600mA.) Substituting another one (from their brother's "Dino" set) perfectly restores normal operation of trains.
Is the bad pack worth cutting open & trying to repair? (It is likely out of warranty.) How sturdy are these things? What happens with these packs any time a car or engine derails and the induced short circuit (caused by the wheels bridging center-to-outside rail) isn't immediately corrected? What kind of fuse or circuit breaker -- any kind of internal protection -- is there?
I'm not going to rush out & buy a replacement at about $30 until I know more about the internals and hopefully others' experiences with this "transformer." Years ago Lionel had a faulty initial run of CW-80's (soon corrected) and I'm wondering if a similar situation exists here.
Heck, it would seem to me that any old 18V DC power pack might be reliably substituted, using the wire and barrel plug from the old Lionel "transformer." Most of those old HO Tyco and Aurora "Model Motoring" packs put out 18 volts at a more robust 1 A or so. At least a momentary short would never faze them. And some had legitimate breakers, as I recall.