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At the Zenith seminars, they always painted the master on/off switch as a UL requirement - to completely turn off a tv.
Philips pioneered the sets with standby power supplies that couldn't be turned off, but the requirement was that they consume less than 5VA. I don't know if the requirement changed, or if there was an engineered solution kind of thing. I have a Philips switching power supply training manual that explains a lot - but nothing about the <5VA requirement, just a mention.
I've seen ultrasonic remote sets turn on at night, when the HVAC kicks in and an inaudible squeal activated the set. I've also seen a stationary bike activate one in a hotel gym, from the friction device on the wheel. And of course, there are the sets that responded to keys being rattled across the room.
Nowadays with IR remotes, it's not a problem. The biggest problem is with something jamming the IR spectra, neutralizing a remote...
Cheers,
__________________
Brian
USN RET 22YRS (Avionics/Cal)
CET-Consumer Repair and Avionics ('88)
"Capacitor Cosmetologist since '79"
When fuses go to work, they quit!
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