No satellite signal on some channels on one box only (other boxes are fine)

[VT001]

We have error message 25 ("Your Sky+ isn't getting a satellite signal.") on only one of three Sky+ HD boxes. Only some channels are affected.

The affected box does not display HD pictures when an HD channel is selected.

The affected box is connected to the screen by a scart cable, the other boxes use HDMI, I think. Could that be the problem?

Moderator note: Amended title

[Mark39]

Partly. You can't receive an HD picture if your Sky box is connected via scart cable. You need an HDMI connection.

With regard to the no satellite signal message, if a restart (switch off at the plug for 4 minutes) doesn't resolve it, there's most likely a problem either with the cable to that box, or the LNB port it's connected to at the dish.

[Annie+UK]

There should be no problem viewing a HD channel via SCART as the box downscales the picture to SD, I have recorded HD channels to VHS via SCART in the past

[VT001]

 OK, so the "No satellite signal" message has nothing to do with the use of a scart cable to the screen. The message is about the quality of the signal coming to the box from the dish.

Is that correct?

[Mark39]

Yes, exactly.