Dead inverter or dead CCFLs?

Discussion in 'General Electronics Chat' started by tom66, Jul 4, 2011.

  1. tom66

    Thread Starter Senior Member

    May 9, 2009
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    I have been given for repair a 15" LCD monitor which has no backlight. So most likely, the inverter or the CCFLs are dead. Question is - which is it? How can I test the CCFL and inverter? I do not have a spare inverter or spare CCFLs...
     
  2. tom66

    Thread Starter Senior Member

    May 9, 2009
    2,613
    214
    Okay, I found a blown fuse on the inverter board. :D I removed the tiny 1206 SMD fuse and replaced it - temporarily - with a solder bridge. Now the monitor lights up for about 1 second then shuts down. So I know the CCFLs are probably good right? Question is, why is the inverter shutting down after 1 second? (Only the inverter - an image is still present when backlight is off.) Perhaps it is overheating? When I first powered it up I forgot to install the insulation, so I got a spark (HV to ground short?) But it doesn't seem to have affected it because it was doing the same thing before the spark.

    EDIT: It turns out the LCD does go blank when the inverter goes blank. Which leads me to the conclusion the inverter is shutting down, and it is signalling the main controller to shut down too.
     
    Last edited: Jul 4, 2011
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