Sky box faulty

[Whiteark]

I turn on tv an sky.  Then after a while a high pitched sound come through tv a d screen goes black.

[oldfella]

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@Whiteark wrote:

I turn on tv an sky.  Then after a while a high pitched sound come through tv a d screen goes black.

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Do you get any message or a picture before this happens @Whiteark ??

[Whiteark]

No. I get no messages.  Nothing .  I have just put tv on without being on sky and tv works fine.  If I leave sky box off for a while is works OK for a few hours then holigh pitched noice etc starts again.  This process continues.  I have tried retting the tv to factory settings  and I have tried turning sky box off.  Taken out card and put back.in.