XPost: alt.home.repair, uk.d-i-y   
   From: tnp@invalid.invalid   
      
   On 03/03/2019 20:49, Max Demian wrote:   
   > Did anyone need to run a TV on DC, or was it just to save having a heavy   
   > mains transformer?   
      
   All valve TVS ran on DC.   
      
   The questin really was if they could be made cheaper by having all te   
   heaters in series designed to run off mains and all the HT simply   
   rectified mains dropped via a big fat resistor to the sort of 200V area   
   that valves rather liked.   
      
   Just dint touch the live chassis if you plugged it in wrong.   
      
      
   >   
   > There were certainly AC/DC *radios* that would cope with 120V to 250V or   
   > so. Needed a whopping great dropper resistor when working on the higher   
   > voltages. I used to have such a (portable valve) radio which would work   
   > on battery as well. The dropper was originally in the mains lead but had   
   > been replaced with a component in the case.   
      
   These days its perfectly possible to have an SMPSU that works from 24VDC   
   to 400V AC.   
      
      
   Without needing to be switched between. I suspect all military kit   
   features such.   
      
      
      
   --   
   If you tell a lie big enough and keep repeating it, people will   
   eventually come to believe it. The lie can be maintained only for such   
   time as the State can shield the people from the political, economic   
   and/or military consequences of the lie. It thus becomes vitally   
   important for the State to use all of its powers to repress dissent, for   
   the truth is the mortal enemy of the lie, and thus by extension, the   
   truth is the greatest enemy of the State.   
      
   Joseph Goebbels   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)