How to check for a TV "hot chassis

Discussion in 'Homework Help' started by edgar007, Jan 31, 2012.

  1. edgar007

    Thread Starter New Member

    Jan 26, 2012
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    New Member: edgar 007
    As a student studying HOME ENTERTAINMENTS SYSTEMS: SERVICING & REPAIRS I am stuck on How to check for a "hot chassis" TV. Does one first place an isolation transformer between the wall outlet and the equipment, ground the chassis to earth? if that be it, what do I then do to ascertain whether the equipment is a "hot chassis"?
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    How about looking for warning signs on the PCB and heat sinks or chassis.
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    1. Check for absence of power transformer.
    2. Check for low resistance between the chassis and one of the prongs on AC plug.
    3. Plug in and turn on TV. Check for AC voltage between chassis and Safety GND. Reverse AC plug and check again.

    Do all of the above.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    You can also get one of them $15 wands that will alert you when > 50V AC/DC is present and wave it around the board to find the "hot" area.

    The chassis should be tied to the green wire (ground) when plugged in, so you should measure some voltage between Black (hot) and ground, and even some voltage between white (neutral) and ground, though not much.

    This is assuming US wiring.

    If it is an LCD/LED/Plasma, the dangers aren't in the same magnitude as CRT Televisions, which would store tens of thousands of volts just waiting for you to put a probe in the wrong spot.
     
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