04-01-2018, 03:42 AM
Although not unknown in New Zealand, live chassis TV receivers were quite rare. Some Philips models of the monochrome era might have been of this type. The same was true for radio chassis, and the use of double-wound isolating power transformers was the accepted norm.
I have never ascertained the legality of live-chassis receivers in NZ, though. I have heard various “stories”, ranging from their being outright illegal to their being frowned upon by electricity distribution authorities because they put DC back on to the mains. Conceivably individual electricity distribution authorities had the power to ban live chassis equipment if they so chose.
The pertinent safety standards also may have played a part. I have a vague notion that in the days before double insulation became commonplace (1970s?) domestic appliances with accessible (not just external) metal parts had to be earthed. Certainly, the need for proper earthing seemed to be well-known for as far back as I can recall. Both NZ and Australia adopted MEN electricity distribution quite early on, with each consumer switchbox having its own MEN link and earthing stake. (As far as I know, the term “MEN” predated the “PME” descriptor used in the UK for what was essentially the same system.) And back in the pre-double insulated days, three-core power leads were the norm for NZ-made TV and radio receivers, as well as for domestic appliances generally.
In the colour TV era, from 1973 in NZ (and as I recall, a bit later in Australia), locally-made receivers were aligned much more closely with their overseas counterparts than had been the case in the monochrome era, and probably in some cases had to be re-engineered with isolated power supplies. The Philips K9, one of the most popular in the 1970s, was one such. In fact, I was surprised to learn that the European original did not have an isolated power supply. And even more surprised to find that “upmarket” European models, such as those from B&O, also had non-isolated power supplies.
It is curious that NZ and Australia took the “high road” in respect of electrical safety. In the NZ case at least, it wasn’t that it was a late starter, so could learn from the mistakes of others. On the contrary, it electrified early by world standards, including developing the Mandeno SWER system for supply to rural back-country areas.
Cheers,
Steve
I have never ascertained the legality of live-chassis receivers in NZ, though. I have heard various “stories”, ranging from their being outright illegal to their being frowned upon by electricity distribution authorities because they put DC back on to the mains. Conceivably individual electricity distribution authorities had the power to ban live chassis equipment if they so chose.
The pertinent safety standards also may have played a part. I have a vague notion that in the days before double insulation became commonplace (1970s?) domestic appliances with accessible (not just external) metal parts had to be earthed. Certainly, the need for proper earthing seemed to be well-known for as far back as I can recall. Both NZ and Australia adopted MEN electricity distribution quite early on, with each consumer switchbox having its own MEN link and earthing stake. (As far as I know, the term “MEN” predated the “PME” descriptor used in the UK for what was essentially the same system.) And back in the pre-double insulated days, three-core power leads were the norm for NZ-made TV and radio receivers, as well as for domestic appliances generally.
In the colour TV era, from 1973 in NZ (and as I recall, a bit later in Australia), locally-made receivers were aligned much more closely with their overseas counterparts than had been the case in the monochrome era, and probably in some cases had to be re-engineered with isolated power supplies. The Philips K9, one of the most popular in the 1970s, was one such. In fact, I was surprised to learn that the European original did not have an isolated power supply. And even more surprised to find that “upmarket” European models, such as those from B&O, also had non-isolated power supplies.
It is curious that NZ and Australia took the “high road” in respect of electrical safety. In the NZ case at least, it wasn’t that it was a late starter, so could learn from the mistakes of others. On the contrary, it electrified early by world standards, including developing the Mandeno SWER system for supply to rural back-country areas.
Cheers,
Steve