T.V ( No display )

Discussion in 'General Electronics Chat' started by donskiter, Dec 2, 2006.

  1. donskiter

    Thread Starter Member

    Nov 17, 2006
    :confused: Good Day..

    Have anyone knows what seem to be the problem? And can give me tips how to troubleshoots Sony TV 25" model KV-25FX1? When i turn on the power theres no display on the screen, i can adjust the volume, change channel and select either tv or video but theres no any display on the screen..I can hear only the audio that confirm all the key button is working ( for ex..when i adjust the volume and change channel).

    By the way i forgot to wrote that the led of the timer is blinking when is turn on
  2. beenthere

    Retired Moderator

    Apr 20, 2004

    You have probably lost high voltage. Unless it's still under warranty, that usually means it's time to get a new one. Without a schematic and test equipment, making a successful repair is not very likely.
  3. Gadget

    Distinguished Member

    Jan 10, 2006
    First thing I'd be checking is tube filiment voltage... normally around 6 volts (AC) on the fil pins of the tube base... (if the tube is glowing then that is all OK).
    The Vertical output stage would be the next easiest step. When this goes faulty it doesn't normally shut down the rest of the set, but what remains of the picture (normally a white horizontal line) is automatically blanked (so nothing on screen) to stop tube burn in. On some sets this can be diagnosed by turning up the "Screen" volts slightly (having first noted the current position of the pot wiper) and a white line may become visable on screen. This would be a positive sign of VOP failure, and replacement of the VOP i/c and assoc fusible resistor may be all that is necessary.
    If the VOP is OK, then next step is to check G1, G2 voltages on the tube base, then checking the R,G, and B cathodes with a scope.
    Past this, and you are gonna have to start getting you head inside a service manual, but in my experiance, this should cover 75% of Sound but no Picture faults.
    If you are not comfortable working around the High voltages involved..(up to 28,000 volts) then take it to someone who is.